Initial commitHEADmaster

51 files changed, 4905 insertions, 0 deletions

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..3421536
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,12 @@
+[submodule "lib/cmsis_device"]
+	path = lib/cmsis_device
+	url = https://github.com/STMicroelectronics/cmsis_device_f3
+[submodule "lib/cmsis_core"]
+	path = lib/cmsis_core
+	url = https://github.com/STMicroelectronics/cmsis_core
+[submodule "lib/hal_driver"]
+	path = lib/hal_driver
+	url = https://github.com/STMicroelectronics/stm32f3xx_hal_driver
+[submodule "lib/musl"]
+	path = lib/musl
+	url = git://git.musl-libc.org/musl
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..d51d2c1
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,160 @@
+
+########################################################################################################################
+# Dependency directories
+########################################################################################################################
+
+CMSIS_DEVICE_DIR 	?= lib/cmsis_device
+CMSIS_CORE_DIR 		?= lib/cmsis_core
+HAL_DIR				?= lib/hal_driver
+MUSL_DIR			?= lib/musl
+
+########################################################################################################################
+# Sources
+########################################################################################################################
+
+C_SOURCES		:= src/main.c
+C_SOURCES		+= src/cobs.c
+C_SOURCES		+= src/clocks.c
+C_SOURCES		+= src/bootloader.c
+C_SOURCES		+= src/interrupts.c
+C_SOURCES		+= src/system_stm32f3xx.c
+C_SOURCES		+= config/fe_config.c
+
+MUSL_SOURCES		+= string/strlen.c
+
+C_SOURCES += $(addprefix $(MUSL_DIR)/src/,$(MUSL_SOURCES))
+
+CXX_SOURCES			+=
+
+BUILDDIR 	?= build
+BINARY 		:= fenris_f302r8tx.elf
+LDSCRIPT 	:= stm32f302r8tx.ld
+
+########################################################################################################################
+# Build parameters
+########################################################################################################################
+
+PREFIX		?= arm-none-eabi-
+
+DEBUG		?= 1
+
+CC			:= $(PREFIX)gcc
+CXX			:= $(PREFIX)g++
+LD			:= $(PREFIX)gcc
+AR			:= $(PREFIX)ar
+AS			:= $(PREFIX)as
+SIZE		:= $(PREFIX)size
+NM			:= $(PREFIX)nm
+OBJCOPY		:= $(PREFIX)objcopy
+OBJDUMP		:= $(PREFIX)objdump
+GDB			:= $(PREFIX)gdb
+
+HOST_CC				?= $(HOST_PREFIX)gcc
+HOST_CXX			?= $(HOST_PREFIX)g++
+HOST_LD				?= $(HOST_PREFIX)gcc
+HOST_AR				?= $(HOST_PREFIX)ar
+HOST_AS				?= $(HOST_PREFIX)as
+HOST_OBJCOPY		?= $(HOST_PREFIX)objcopy
+HOST_OBJDUMP		?= $(HOST_PREFIX)objdump
+
+PYTHON3 ?= python3
+DOT		?= dot
+
+CMSIS_DIR_ABS 		:= $(abspath $(CMSIS_DIR))
+
+ARCH_FLAGS		?= -mthumb -mcpu=cortex-m4 -mfloat-abi=hard -mfpu=fpv4-sp-d16
+SYSTEM_FLAGS	?= -nostdlib -ffreestanding -nostartfiles
+
+CFLAGS				+= -Iinclude -Iconfig
+CFLAGS				+= -I$(BUILDDIR)
+CFLAGS				+= -I$(CMSIS_DEVICE_DIR)/Include -I$(CMSIS_CORE_DIR)/Include
+CFLAGS				+= -I$(abspath include/musl_include_shims)
+
+CFLAGS			+= -Os -std=gnu11 -g -DSTM32F302x8 -DSTM32F3 -DDEBUG=$(DEBUG)
+CFLAGS			+= $(ARCH_FLAGS) $(SYSTEM_FLAGS)
+CFLAGS			+= -fno-common -ffunction-sections -fdata-sections
+
+# for musl
+CFLAGS			+= -Dhidden=
+
+CXXFLAGS	+= -Os -g
+CXXFLAGS	+= $(ARCH_FLAGS) $(SYSTEM_FLAGS)
+CXXFLAGS	+= -fno-common -ffunction-sections -fdata-sections
+CXXFLAGS	+= -Wall -Wextra -Wshadow -Wundef -Wredundant-decls
+CXXFLAGS	+= -I.
+
+LDFLAGS			+= $(ARCH_FLAGS) $(SYSTEM_FLAGS)
+
+LIBS		+= -lgcc
+LDFLAGS		+= -Wl,--gc-sections
+
+LINKMEM_FLAGS ?= --trim-stubs=startup_stm32f302x8.o --trace-sections .isr_vector --highlight-subdirs $(BUILDDIR)
+
+OBJS := $(addprefix $(BUILDDIR)/,$(C_SOURCES:.c=.o) $(CXX_SOURCES:.cpp=.o))
+
+ALL_OBJS := $(OBJS)
+ALL_OBJS += $(BUILDDIR)/startup_stm32f302x8.o
+
+########################################################################################################################
+# Rules
+########################################################################################################################
+
+all: binsize
+
+.PHONY: binsize
+binsize: $(BUILDDIR)/$(BINARY) $(BUILDDIR)/$(BINARY:.elf=-symbol-sizes.pdf)
+	$(LD) -T$(LDSCRIPT) $(LDFLAGS) -Wl,--print-memory-usage -o /dev/null $(ALL_OBJS) $(LIBS)
+	@echo
+	@echo "▐▬▬▬▌ SyMbOL sIzE HiGhScORe LiSt ▐▬▬▬▌"
+	$(NM) --print-size --size-sort --radix=d $< | tail -n 20
+
+$(BUILDDIR)/generated: ; mkdir -p $@
+
+.PRECIOUS: $(BUILDDIR)/$(BINARY) 
+$(BUILDDIR)/$(BINARY) $(BUILDDIR)/$(BINARY:.elf=.map) &: $(ALL_OBJS)
+	$(LD) -T$(LDSCRIPT) $(LDFLAGS) -o $@ -Wl,-Map=$(BUILDDIR)/$(BINARY:.elf=.map) $^ $(LIBS)
+
+build/$(BINARY:.elf=-symbol-sizes.dot): $(ALL_OBJS)
+	$(PYTHON3) tools/linkmem.py $(LINKMEM_FLAGS) $(LD) -T$(LDSCRIPT) $(LDFLAGS) $^ $(LIBS) > $@
+
+%.pdf: %.dot
+	$(DOT) -T pdf $< -o $@
+
+%.dot: %.elf
+	r2 -a arm -qc 'aa;agRd' $< 2>/dev/null >$@
+
+$(BUILDDIR)/%.o: %.s
+	mkdir -p $(@D)
+	$(CC) $(COMMON_CFLAGS) $(CFLAGS) $(INT_CFLAGS) -o $@ -c $<
+
+$(BUILDDIR)/src/%.o: src/%.c
+	mkdir -p $(@D)
+	$(CC) $(COMMON_CFLAGS) $(CFLAGS) $(INT_CFLAGS) -o $@ -c $<
+
+$(BUILDDIR)/src/%.o: src/%.cpp
+	mkdir -p $(@D)
+	$(CXX) $(CXXFLAGS) -o $@ -c $<
+
+$(BUILDDIR)/generated/%.o: $(BUILDDIR)/generated/%.c
+	mkdir -p $(@D)
+	$(CC) $(COMMON_CFLAGS) $(CFLAGS) $(INT_CFLAGS) -o $@ -c $<
+
+$(BUILDDIR)/%.o: %.c
+	mkdir -p $(@D)
+	$(CC) $(COMMON_CFLAGS) $(CFLAGS) $(EXT_CFLAGS) -o $@ -c $<
+
+clean:
+	rm -rf $(BUILDDIR)/src
+	rm -rf $(BUILDDIR)/generated
+	rm -f $(BUILDDIR)/$(BINARY)
+	rm -f $(BUILDDIR)/$(BINARY:.elf=.map)
+	rm -f $(BUILDDIR)/$(BINARY:.elf=-symbol-sizes.dot)
+	rm -f $(BUILDDIR)/$(BINARY:.elf=-symbol-sizes.pdf)
+	rm -f $(BUILDDIR)/tools/freq_meas_test
+
+mrproper: clean
+	rm -rf build
+
+.PHONY: clean mrproper
+
+-include $(OBJS:.o=.d)
diff --git a/config/fe_config.c b/config/fe_config.c
new file mode 100644
index 0000000..f486cf0
--- /dev/null
+++ b/config/fe_config.c
@@ -0,0 +1,17 @@
+#ifndef __FE_CONFIG_H__
+#define __FE_CONFIG_H__
+
+#include <fe_config_backend.h>
+
+const struct fe_config_def fe_config = {
+    .bootloader_enable_pin = { FE_CONFIG_GPIOB, 0 },
+    .bootloader_enable_level = 1,
+    .signature_disable_pin = { FE_CONFIG_GPIOB, 1 },
+    .signature_disable_level = 1,
+    .usart = FE_CONFIG_USART1_PB7,
+    .baudrate = 115200,
+    /* The following string happens to be a valid COBS frame. */
+    .welcome_string = "Fenris Bootloader\r\n(c) 2020 jaseg\r\nSee https://git.jaseg.de/fenris  \r\n",
+};
+
+#endif /* __FE_CONFIG_H__ */
diff --git a/include/bootloader.h b/include/bootloader.h
new file mode 100644
index 0000000..c1b9820
--- /dev/null
+++ b/include/bootloader.h
@@ -0,0 +1,22 @@
+#ifndef __FE_BOOTLOADER_H__
+#define __FE_BOOTLOADER_H__
+
+#include <fe_global.h>
+
+void fe_jump_to_application(void) __attribute__ ((noreturn)); 
+void fe_system_reset(void) __attribute__ ((noreturn)); 
+bool fe_check_img_valid(void);
+
+void flash_unlock(void);
+void flash_lock(void);
+int flash_erase_page(size_t addr);
+int flash_write(size_t addr, char *buf, size_t len);
+int erase_user_flash(void);
+
+#define PAGE_SIZE 0x2000
+
+extern size_t flash_base;
+extern size_t flash_size;
+extern size_t bootloader_size;
+
+#endif /* __FE_BOOTLOADER_H__ */
diff --git a/include/cobs.h b/include/cobs.h
new file mode 100644
index 0000000..8c4f429
--- /dev/null
+++ b/include/cobs.h
@@ -0,0 +1,23 @@
+#ifndef __COBS_H__
+#define __COBS_H__
+
+#include <stdint.h>
+#include <unistd.h>
+#include <string.h>
+
+
+struct cobs_decode_state {
+    size_t p;
+    size_t c;
+};
+
+
+ssize_t cobs_encode(char *dst, size_t dstlen, char *src, size_t srclen);
+ssize_t cobs_decode(char *dst, size_t dstlen, char *src, size_t srclen);
+
+int cobs_encode_usart(int (*output)(void*, char), void *userdata, char *src, size_t srclen);
+
+void cobs_decode_incremental_initialize(struct cobs_decode_state *state);
+int cobs_decode_incremental(struct cobs_decode_state *state, char *dst, size_t dstlen, char src);
+
+#endif//__COBS_H__
diff --git a/include/fe_clocks.h b/include/fe_clocks.h
new file mode 100644
index 0000000..681feae
--- /dev/null
+++ b/include/fe_clocks.h
@@ -0,0 +1,14 @@
+#ifndef __FE_CLOCKS_H__
+#define __FE_CLOCKS_H__
+
+extern unsigned int sysclk_speed;
+extern unsigned int ahb_speed;
+extern unsigned int apb1_speed;
+extern unsigned int apb2_speed;
+extern unsigned int apb1_timer_speed;
+extern unsigned int apb2_timer_speed;
+
+void fe_config_clocks(void);
+void delay_ms(int ms);
+
+#endif /* __FE_CLOCKS_H__ */
diff --git a/include/fe_config_backend.h b/include/fe_config_backend.h
new file mode 100644
index 0000000..e0d6690
--- /dev/null
+++ b/include/fe_config_backend.h
@@ -0,0 +1,40 @@
+#ifndef __FE_CONFIG_BACKEND_H__
+#define __FE_CONFIG_BACKEND_H__
+
+#include <fe_global.h>
+
+#define FE_CONFIG_GPIOA RCC_AHBENR_GPIOAEN, GPIOA
+#define FE_CONFIG_GPIOB RCC_AHBENR_GPIOBEN, GPIOB
+#define FE_CONFIG_GPIOC RCC_AHBENR_GPIOCEN, GPIOC
+#define FE_CONFIG_GPIOD RCC_AHBENR_GPIODEN, GPIOD
+#define FE_CONFIG_GPIOF RCC_AHBENR_GPIOFEN, GPIOF
+
+enum fe_config_usart {
+    FE_CONFIG_USART1_PB7,
+    FE_CONFIG_USART_COUNT
+};
+
+struct fe_config_gpiodef {
+    uint32_t rcc_ahbenr_flags;
+    GPIO_TypeDef *gpio;
+    int pin_number; 
+};
+
+struct fe_config_def {
+    struct fe_config_gpiodef bootloader_enable_pin;
+    int bootloader_enable_level;
+
+    struct fe_config_gpiodef signature_disable_pin;
+    int signature_disable_level;
+
+    enum fe_config_usart usart;
+    int baudrate;
+    
+    const char *welcome_string;
+};
+
+extern const struct fe_config_def fe_config;
+
+void gpio_config(GPIO_TypeDef *gpio, int pin, int mode, int speed, int pullups, int alt);
+
+#endif /* __FE_CONFIG_BACKEND_H__ */
diff --git a/include/fe_global.h b/include/fe_global.h
new file mode 100644
index 0000000..78a269f
--- /dev/null
+++ b/include/fe_global.h
@@ -0,0 +1,19 @@
+#ifndef __FE_GLOBAL_H__
+#define __FE_GLOBAL_H__
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <sys/types.h>
+
+#include <stm32f302x8.h>
+
+#define UNUSED(x) ((void) x)
+#define ARRAY_LENGTH(x) (sizeof(x) / sizeof(x[0]))
+#define unused_a __attribute__((unused))
+
+extern uint64_t sys_time_millis;
+
+void __libc_init_array(void);
+
+#endif /* __FE_GLOBAL_H__ */
diff --git a/include/fe_interrupts.h b/include/fe_interrupts.h
new file mode 100644
index 0000000..9a85fe0
--- /dev/null
+++ b/include/fe_interrupts.h
@@ -0,0 +1,14 @@
+#ifndef __FE_INTERRUPTS_H__
+#define __FE_INTERRUPTS_H__
+
+void NMI_Handler(void);
+void HardFault_Handler(void);
+void MemManage_Handler(void);
+void BusFault_Handler(void);
+void UsageFault_Handler(void);
+void SVC_Handler(void);
+void DebugMon_Handler(void);
+void PendSV_Handler(void);
+void SysTick_Handler(void);
+
+#endif /* __FE_INTERRUPTS_H__ */
diff --git a/include/musl_include_shims/bits/alltypes.h b/include/musl_include_shims/bits/alltypes.h
new file mode 100644
index 0000000..581ca85
--- /dev/null
+++ b/include/musl_include_shims/bits/alltypes.h
@@ -0,0 +1,23 @@
+
+/* shim file for musl */
+
+#ifndef __MUSL_SHIM_BITS_ALLTYPES_H__
+#define __MUSL_SHIM_BITS_ALLTYPES_H__
+
+#define _REDIR_TIME64 1
+#define _Addr int
+#define _Int64 long long
+#define _Reg int
+
+#define __BYTE_ORDER 1234
+
+#define __LONG_MAX 0x7fffffffL
+
+#ifndef __cplusplus
+typedef unsigned wchar_t;
+#endif
+
+typedef float float_t;
+typedef double double_t;
+
+#endif /* __MUSL_SHIM_BITS_ALLTYPES_H__ */
diff --git a/include/musl_include_shims/endian.h b/include/musl_include_shims/endian.h
new file mode 100644
index 0000000..172c432
--- /dev/null
+++ b/include/musl_include_shims/endian.h
@@ -0,0 +1,80 @@
+#ifndef _ENDIAN_H
+#define _ENDIAN_H
+
+#include <features.h>
+
+#define __NEED_uint16_t
+#define __NEED_uint32_t
+#define __NEED_uint64_t
+
+#include <bits/alltypes.h>
+
+#define __PDP_ENDIAN 3412
+
+#define BIG_ENDIAN __BIG_ENDIAN
+#define LITTLE_ENDIAN __LITTLE_ENDIAN
+#define PDP_ENDIAN __PDP_ENDIAN
+#define BYTE_ORDER __BYTE_ORDER
+
+static __inline uint16_t __bswap16(uint16_t __x)
+{
+	return __x<<8 | __x>>8;
+}
+
+static __inline uint32_t __bswap32(uint32_t __x)
+{
+	return __x>>24 | __x>>8&0xff00 | __x<<8&0xff0000 | __x<<24;
+}
+
+static __inline uint64_t __bswap64(uint64_t __x)
+{
+	return __bswap32(__x)+0ULL<<32 | __bswap32(__x>>32);
+}
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define htobe16(x) __bswap16(x)
+#define be16toh(x) __bswap16(x)
+#define htobe32(x) __bswap32(x)
+#define be32toh(x) __bswap32(x)
+#define htobe64(x) __bswap64(x)
+#define be64toh(x) __bswap64(x)
+#define htole16(x) (uint16_t)(x)
+#define le16toh(x) (uint16_t)(x)
+#define htole32(x) (uint32_t)(x)
+#define le32toh(x) (uint32_t)(x)
+#define htole64(x) (uint64_t)(x)
+#define le64toh(x) (uint64_t)(x)
+#else
+#define htobe16(x) (uint16_t)(x)
+#define be16toh(x) (uint16_t)(x)
+#define htobe32(x) (uint32_t)(x)
+#define be32toh(x) (uint32_t)(x)
+#define htobe64(x) (uint64_t)(x)
+#define be64toh(x) (uint64_t)(x)
+#define htole16(x) __bswap16(x)
+#define le16toh(x) __bswap16(x)
+#define htole32(x) __bswap32(x)
+#define le32toh(x) __bswap32(x)
+#define htole64(x) __bswap64(x)
+#define le64toh(x) __bswap64(x)
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+#define betoh16(x) __bswap16(x)
+#define betoh32(x) __bswap32(x)
+#define betoh64(x) __bswap64(x)
+#define letoh16(x) (uint16_t)(x)
+#define letoh32(x) (uint32_t)(x)
+#define letoh64(x) (uint64_t)(x)
+#else
+#define betoh16(x) (uint16_t)(x)
+#define betoh32(x) (uint32_t)(x)
+#define betoh64(x) (uint64_t)(x)
+#define letoh16(x) __bswap16(x)
+#define letoh32(x) __bswap32(x)
+#define letoh64(x) __bswap64(x)
+#endif
+#endif
+
+#endif
diff --git a/include/musl_include_shims/features.h b/include/musl_include_shims/features.h
new file mode 100644
index 0000000..85cfb72
--- /dev/null
+++ b/include/musl_include_shims/features.h
@@ -0,0 +1,40 @@
+#ifndef _FEATURES_H
+#define _FEATURES_H
+
+#if defined(_ALL_SOURCE) && !defined(_GNU_SOURCE)
+#define _GNU_SOURCE 1
+#endif
+
+#if defined(_DEFAULT_SOURCE) && !defined(_BSD_SOURCE)
+#define _BSD_SOURCE 1
+#endif
+
+#if !defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE) \
+ && !defined(_XOPEN_SOURCE) && !defined(_GNU_SOURCE) \
+ && !defined(_BSD_SOURCE) && !defined(__STRICT_ANSI__)
+#define _BSD_SOURCE 1
+#define _XOPEN_SOURCE 700
+#endif
+
+#if __STDC_VERSION__ >= 199901L
+#define __restrict restrict
+#elif !defined(__GNUC__)
+#define __restrict
+#endif
+
+#if __STDC_VERSION__ >= 199901L || defined(__cplusplus)
+#define __inline inline
+#elif !defined(__GNUC__)
+#define __inline
+#endif
+
+#if __STDC_VERSION__ >= 201112L
+#elif defined(__GNUC__)
+#define _Noreturn __attribute__((__noreturn__))
+#else
+#define _Noreturn
+#endif
+
+#define __REDIR(x,y) __typeof__(x) x __asm__(#y)
+
+#endif
diff --git a/include/musl_include_shims/fp_arch.h b/include/musl_include_shims/fp_arch.h
new file mode 100644
index 0000000..f5bab6d
--- /dev/null
+++ b/include/musl_include_shims/fp_arch.h
@@ -0,0 +1,6 @@
+#ifndef __MUSL_SHIM_FP_ARCH_H__
+#define __MUSL_SHIM_FP_ARCH_H__
+
+#define hidden
+
+#endif /* __MUSL_SHIM_FP_ARCH_H__ */
diff --git a/include/musl_include_shims/libm.h b/include/musl_include_shims/libm.h
new file mode 100644
index 0000000..d48135d
--- /dev/null
+++ b/include/musl_include_shims/libm.h
@@ -0,0 +1,270 @@
+#ifndef _LIBM_H
+#define _LIBM_H
+
+#include <stdint.h>
+#include <float.h>
+#include <math.h>
+#include <endian.h>
+#include "fp_arch.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __LITTLE_ENDIAN
+union ldshape {
+	long double f;
+	struct {
+		uint64_t m;
+		uint16_t se;
+	} i;
+};
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __BIG_ENDIAN
+/* This is the m68k variant of 80-bit long double, and this definition only works
+ * on archs where the alignment requirement of uint64_t is <= 4. */
+union ldshape {
+	long double f;
+	struct {
+		uint16_t se;
+		uint16_t pad;
+		uint64_t m;
+	} i;
+};
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __LITTLE_ENDIAN
+union ldshape {
+	long double f;
+	struct {
+		uint64_t lo;
+		uint32_t mid;
+		uint16_t top;
+		uint16_t se;
+	} i;
+	struct {
+		uint64_t lo;
+		uint64_t hi;
+	} i2;
+};
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384 && __BYTE_ORDER == __BIG_ENDIAN
+union ldshape {
+	long double f;
+	struct {
+		uint16_t se;
+		uint16_t top;
+		uint32_t mid;
+		uint64_t lo;
+	} i;
+	struct {
+		uint64_t hi;
+		uint64_t lo;
+	} i2;
+};
+#else
+#error Unsupported long double representation
+#endif
+
+/* Support non-nearest rounding mode.  */
+#define WANT_ROUNDING 1
+/* Support signaling NaNs.  */
+#define WANT_SNAN 0
+
+#if WANT_SNAN
+#error SNaN is unsupported
+#else
+#define issignalingf_inline(x) 0
+#define issignaling_inline(x) 0
+#endif
+
+#ifndef TOINT_INTRINSICS
+#define TOINT_INTRINSICS 0
+#endif
+
+#if TOINT_INTRINSICS
+/* Round x to nearest int in all rounding modes, ties have to be rounded
+   consistently with converttoint so the results match.  If the result
+   would be outside of [-2^31, 2^31-1] then the semantics is unspecified.  */
+static double_t roundtoint(double_t);
+
+/* Convert x to nearest int in all rounding modes, ties have to be rounded
+   consistently with roundtoint.  If the result is not representible in an
+   int32_t then the semantics is unspecified.  */
+static int32_t converttoint(double_t);
+#endif
+
+/* Helps static branch prediction so hot path can be better optimized.  */
+#ifdef __GNUC__
+#define predict_true(x) __builtin_expect(!!(x), 1)
+#define predict_false(x) __builtin_expect(x, 0)
+#else
+#define predict_true(x) (x)
+#define predict_false(x) (x)
+#endif
+
+/* Evaluate an expression as the specified type. With standard excess
+   precision handling a type cast or assignment is enough (with
+   -ffloat-store an assignment is required, in old compilers argument
+   passing and return statement may not drop excess precision).  */
+
+static inline float eval_as_float(float x)
+{
+	float y = x;
+	return y;
+}
+
+static inline double eval_as_double(double x)
+{
+	double y = x;
+	return y;
+}
+
+/* fp_barrier returns its input, but limits code transformations
+   as if it had a side-effect (e.g. observable io) and returned
+   an arbitrary value.  */
+
+#ifndef fp_barrierf
+#define fp_barrierf fp_barrierf
+static inline float fp_barrierf(float x)
+{
+	volatile float y = x;
+	return y;
+}
+#endif
+
+#ifndef fp_barrier
+#define fp_barrier fp_barrier
+static inline double fp_barrier(double x)
+{
+	volatile double y = x;
+	return y;
+}
+#endif
+
+#ifndef fp_barrierl
+#define fp_barrierl fp_barrierl
+static inline long double fp_barrierl(long double x)
+{
+	volatile long double y = x;
+	return y;
+}
+#endif
+
+/* fp_force_eval ensures that the input value is computed when that's
+   otherwise unused.  To prevent the constant folding of the input
+   expression, an additional fp_barrier may be needed or a compilation
+   mode that does so (e.g. -frounding-math in gcc). Then it can be
+   used to evaluate an expression for its fenv side-effects only.   */
+
+#ifndef fp_force_evalf
+#define fp_force_evalf fp_force_evalf
+static inline void fp_force_evalf(float x)
+{
+	volatile float y;
+	y = x;
+}
+#endif
+
+#ifndef fp_force_eval
+#define fp_force_eval fp_force_eval
+static inline void fp_force_eval(double x)
+{
+	volatile double y;
+	y = x;
+}
+#endif
+
+#ifndef fp_force_evall
+#define fp_force_evall fp_force_evall
+static inline void fp_force_evall(long double x)
+{
+	volatile long double y;
+	y = x;
+}
+#endif
+
+#define FORCE_EVAL(x) do {                        \
+	if (sizeof(x) == sizeof(float)) {         \
+		fp_force_evalf(x);                \
+	} else if (sizeof(x) == sizeof(double)) { \
+		fp_force_eval(x);                 \
+	} else {                                  \
+		fp_force_evall(x);                \
+	}                                         \
+} while(0)
+
+#define asuint(f) ((union{float _f; uint32_t _i;}){f})._i
+#define asfloat(i) ((union{uint32_t _i; float _f;}){i})._f
+#define asuint64(f) ((union{double _f; uint64_t _i;}){f})._i
+#define asdouble(i) ((union{uint64_t _i; double _f;}){i})._f
+
+#define EXTRACT_WORDS(hi,lo,d)                    \
+do {                                              \
+  uint64_t __u = asuint64(d);                     \
+  (hi) = __u >> 32;                               \
+  (lo) = (uint32_t)__u;                           \
+} while (0)
+
+#define GET_HIGH_WORD(hi,d)                       \
+do {                                              \
+  (hi) = asuint64(d) >> 32;                       \
+} while (0)
+
+#define GET_LOW_WORD(lo,d)                        \
+do {                                              \
+  (lo) = (uint32_t)asuint64(d);                   \
+} while (0)
+
+#define INSERT_WORDS(d,hi,lo)                     \
+do {                                              \
+  (d) = asdouble(((uint64_t)(hi)<<32) | (uint32_t)(lo)); \
+} while (0)
+
+#define SET_HIGH_WORD(d,hi)                       \
+  INSERT_WORDS(d, hi, (uint32_t)asuint64(d))
+
+#define SET_LOW_WORD(d,lo)                        \
+  INSERT_WORDS(d, asuint64(d)>>32, lo)
+
+#define GET_FLOAT_WORD(w,d)                       \
+do {                                              \
+  (w) = asuint(d);                                \
+} while (0)
+
+#define SET_FLOAT_WORD(d,w)                       \
+do {                                              \
+  (d) = asfloat(w);                               \
+} while (0)
+
+hidden int    __rem_pio2_large(double*,double*,int,int,int);
+
+hidden int    __rem_pio2(double,double*);
+hidden double __sin(double,double,int);
+hidden double __cos(double,double);
+hidden double __tan(double,double,int);
+hidden double __expo2(double);
+
+hidden int    __rem_pio2f(float,double*);
+hidden float  __sindf(double);
+hidden float  __cosdf(double);
+hidden float  __tandf(double,int);
+hidden float  __expo2f(float);
+
+hidden int __rem_pio2l(long double, long double *);
+hidden long double __sinl(long double, long double, int);
+hidden long double __cosl(long double, long double);
+hidden long double __tanl(long double, long double, int);
+
+hidden long double __polevll(long double, const long double *, int);
+hidden long double __p1evll(long double, const long double *, int);
+
+hidden double __lgamma_r(double, int *);
+hidden float __lgammaf_r(float, int *);
+
+/* error handling functions */
+hidden float __math_xflowf(uint32_t, float);
+hidden float __math_uflowf(uint32_t);
+hidden float __math_oflowf(uint32_t);
+hidden float __math_divzerof(uint32_t);
+hidden float __math_invalidf(float);
+hidden double __math_xflow(uint32_t, double);
+hidden double __math_uflow(uint32_t);
+hidden double __math_oflow(uint32_t);
+hidden double __math_divzero(uint32_t);
+hidden double __math_invalid(double);
+
+#endif
diff --git a/include/stm32_hal_conf.h b/include/stm32_hal_conf.h
new file mode 100644
index 0000000..0b5d0c3
--- /dev/null
+++ b/include/stm32_hal_conf.h
@@ -0,0 +1,337 @@
+/**
+  ******************************************************************************
+  * @file    stm32f3xx_hal_conf.h
+  * @author  MCD Application Team
+  * @brief   HAL configuration file.
+  ******************************************************************************
+  * @attention
+  *
+  * <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
+  * All rights reserved.</center></h2>
+  *
+  * This software component is licensed by ST under BSD 3-Clause license,
+  * the "License"; You may not use this file except in compliance with the
+  * License. You may obtain a copy of the License at:
+  *                        opensource.org/licenses/BSD-3-Clause
+  *
+  ******************************************************************************
+  */ 
+
+/* Define to prevent recursive inclusion -------------------------------------*/
+#ifndef __STM32F3xx_HAL_CONF_H
+#define __STM32F3xx_HAL_CONF_H
+
+#ifdef __cplusplus
+ extern "C" {
+#endif
+
+/* Exported types ------------------------------------------------------------*/
+/* Exported constants --------------------------------------------------------*/
+
+/* ########################## Module Selection ############################## */
+/**
+  * @brief This is the list of modules to be used in the HAL driver 
+  */
+#define HAL_MODULE_ENABLED
+// #define HAL_ADC_MODULE_ENABLED
+// #define HAL_CAN_MODULE_ENABLED
+/* #define HAL_CAN_LEGACY_MODULE_ENABLED */
+// #define HAL_CEC_MODULE_ENABLED
+// #define HAL_COMP_MODULE_ENABLED
+// #define HAL_CORTEX_MODULE_ENABLED
+// #define HAL_CRC_MODULE_ENABLED
+// #define HAL_DAC_MODULE_ENABLED
+// #define HAL_DMA_MODULE_ENABLED
+#define HAL_FLASH_MODULE_ENABLED
+// #define HAL_GPIO_MODULE_ENABLED
+// #define HAL_EXTI_MODULE_ENABLED
+// #define HAL_HRTIM_MODULE_ENABLED
+// #define HAL_I2C_MODULE_ENABLED
+// #define HAL_I2S_MODULE_ENABLED
+// #define HAL_IRDA_MODULE_ENABLED
+// #define HAL_IWDG_MODULE_ENABLED
+// #define HAL_OPAMP_MODULE_ENABLED
+// #define HAL_PCD_MODULE_ENABLED
+// #define HAL_PWR_MODULE_ENABLED
+// #define HAL_RCC_MODULE_ENABLED
+// #define HAL_RTC_MODULE_ENABLED
+// #define HAL_SDADC_MODULE_ENABLED
+// #define HAL_SMARTCARD_MODULE_ENABLED
+// #define HAL_SMBUS_MODULE_ENABLED
+// #define HAL_SPI_MODULE_ENABLED
+// #define HAL_TIM_MODULE_ENABLED
+// #define HAL_TSC_MODULE_ENABLED
+// #define HAL_UART_MODULE_ENABLED
+// #define HAL_USART_MODULE_ENABLED
+// #define HAL_WWDG_MODULE_ENABLED
+
+/* ########################## HSE/HSI Values adaptation ##################### */
+/**
+  * @brief Adjust the value of External High Speed oscillator (HSE) used in your application.
+  *        This value is used by the RCC HAL module to compute the system frequency
+  *        (when HSE is used as system clock source, directly or through the PLL).  
+  */
+#if !defined  (HSE_VALUE) 
+  #define HSE_VALUE    (8000000U) /*!< Value of the External oscillator in Hz */
+#endif /* HSE_VALUE */
+
+/**
+  * @brief In the following line adjust the External High Speed oscillator (HSE) Startup 
+  *        Timeout value 
+  */
+#if !defined  (HSE_STARTUP_TIMEOUT)
+  #define HSE_STARTUP_TIMEOUT    (100U)   /*!< Time out for HSE start up, in ms */
+#endif /* HSE_STARTUP_TIMEOUT */
+
+/**
+  * @brief Internal High Speed oscillator (HSI) value.
+  *        This value is used by the RCC HAL module to compute the system frequency
+  *        (when HSI is used as system clock source, directly or through the PLL). 
+  */
+#if !defined  (HSI_VALUE)
+  #define HSI_VALUE    (8000000U) /*!< Value of the Internal oscillator in Hz*/
+#endif /* HSI_VALUE */
+
+/**
+  * @brief In the following line adjust the Internal High Speed oscillator (HSI) Startup 
+  *        Timeout value 
+  */
+#if !defined  (HSI_STARTUP_TIMEOUT) 
+ #define HSI_STARTUP_TIMEOUT   (5000U) /*!< Time out for HSI start up */
+#endif /* HSI_STARTUP_TIMEOUT */  
+
+/**
+  * @brief Internal Low Speed oscillator (LSI) value.
+  */
+#if !defined  (LSI_VALUE) 
+ #define LSI_VALUE  (40000U)    
+#endif /* LSI_VALUE */                      /*!< Value of the Internal Low Speed oscillator in Hz
+                                             The real value may vary depending on the variations
+                                             in voltage and temperature.  */
+/**
+  * @brief External Low Speed oscillator (LSE) value.
+  */
+#if !defined  (LSE_VALUE)
+ #define LSE_VALUE  (32768U)    /*!< Value of the External Low Speed oscillator in Hz */
+#endif /* LSE_VALUE */
+
+/**
+  * @brief Time out for LSE start up value in ms.
+  */
+#if !defined  (LSE_STARTUP_TIMEOUT)
+  #define LSE_STARTUP_TIMEOUT    (5000U)   /*!< Time out for LSE start up, in ms */
+#endif /* LSE_STARTUP_TIMEOUT */     
+
+/**
+  * @brief External clock source for I2S peripheral
+  *        This value is used by the I2S HAL module to compute the I2S clock source 
+  *        frequency, this source is inserted directly through I2S_CKIN pad.
+  *        - External clock generated through external PLL component on EVAL 303 (based on MCO or crystal)
+  *        - External clock not generated on EVAL 373
+  */
+#if !defined  (EXTERNAL_CLOCK_VALUE)
+  #define EXTERNAL_CLOCK_VALUE    (8000000U) /*!< Value of the External oscillator in Hz*/
+#endif /* EXTERNAL_CLOCK_VALUE */
+
+/* Tip: To avoid modifying this file each time you need to use different HSE,
+   ===  you can define the HSE value in your toolchain compiler preprocessor. */
+
+/* ########################### System Configuration ######################### */
+/**
+  * @brief This is the HAL system configuration section
+  */     
+#define  VDD_VALUE                    (3300U) /*!< Value of VDD in mv */
+#define  TICK_INT_PRIORITY            ((uint32_t)(1U<<__NVIC_PRIO_BITS) - 1U)   /*!< tick interrupt priority (lowest by default) */
+#define  USE_RTOS                     0U     
+#define  PREFETCH_ENABLE              1U              
+#define  INSTRUCTION_CACHE_ENABLE     0U
+#define  DATA_CACHE_ENABLE            0U
+#define  USE_SPI_CRC                  1U
+
+#define  USE_HAL_ADC_REGISTER_CALLBACKS         0U /* ADC register callback disabled       */
+#define  USE_HAL_CAN_REGISTER_CALLBACKS         0U /* CAN register callback disabled       */
+#define  USE_HAL_COMP_REGISTER_CALLBACKS        0U /* COMP register callback disabled      */
+#define  USE_HAL_CEC_REGISTER_CALLBACKS         0U /* CEC register callback disabled       */
+#define  USE_HAL_DAC_REGISTER_CALLBACKS         0U /* DAC register callback disabled       */
+#define  USE_HAL_SRAM_REGISTER_CALLBACKS        0U /* SRAM register callback disabled      */
+#define  USE_HAL_SMBUS_REGISTER_CALLBACKS       0U /* SMBUS register callback disabled     */
+#define  USE_HAL_SDADC_REGISTER_CALLBACKS       0U /* SDADC register callback disabled     */
+#define  USE_HAL_NAND_REGISTER_CALLBACKS        0U /* NAND register callback disabled      */
+#define  USE_HAL_NOR_REGISTER_CALLBACKS         0U /* NOR register callback disabled       */
+#define  USE_HAL_PCCARD_REGISTER_CALLBACKS      0U /* PCCARD register callback disabled    */
+#define  USE_HAL_HRTIM_REGISTER_CALLBACKS       0U /* HRTIM register callback disabled     */
+#define  USE_HAL_I2C_REGISTER_CALLBACKS         0U /* I2C register callback disabled       */
+#define  USE_HAL_UART_REGISTER_CALLBACKS        0U /* UART register callback disabled      */
+#define  USE_HAL_USART_REGISTER_CALLBACKS       0U /* USART register callback disabled     */
+#define  USE_HAL_IRDA_REGISTER_CALLBACKS        0U /* IRDA register callback disabled      */
+#define  USE_HAL_SMARTCARD_REGISTER_CALLBACKS   0U /* SMARTCARD register callback disabled */
+#define  USE_HAL_WWDG_REGISTER_CALLBACKS        0U /* WWDG register callback disabled      */
+#define  USE_HAL_OPAMP_REGISTER_CALLBACKS       0U /* OPAMP register callback disabled     */
+#define  USE_HAL_RTC_REGISTER_CALLBACKS         0U /* RTC register callback disabled       */
+#define  USE_HAL_SPI_REGISTER_CALLBACKS         0U /* SPI register callback disabled       */
+#define  USE_HAL_I2S_REGISTER_CALLBACKS         0U /* I2S register callback disabled       */
+#define  USE_HAL_TIM_REGISTER_CALLBACKS         0U /* TIM register callback disabled       */
+#define  USE_HAL_TSC_REGISTER_CALLBACKS         0U /* TSC register callback disabled       */
+#define  USE_HAL_PCD_REGISTER_CALLBACKS         0U /* PCD register callback disabled       */
+
+/* ########################## Assert Selection ############################## */
+/**
+  * @brief Uncomment the line below to expanse the "assert_param" macro in the 
+  *        HAL drivers code
+  */
+/*#define USE_FULL_ASSERT    1*/
+
+/* Includes ------------------------------------------------------------------*/
+/**
+  * @brief Include module's header file 
+  */
+
+#ifdef HAL_RCC_MODULE_ENABLED
+ #include "stm32f3xx_hal_rcc.h"
+#endif /* HAL_RCC_MODULE_ENABLED */
+
+#ifdef HAL_GPIO_MODULE_ENABLED
+ #include "stm32f3xx_hal_gpio.h"
+#endif /* HAL_GPIO_MODULE_ENABLED */
+
+#ifdef HAL_EXTI_MODULE_ENABLED
+ #include "stm32f3xx_hal_exti.h"
+#endif /* HAL_EXTI_MODULE_ENABLED */
+
+#ifdef HAL_DMA_MODULE_ENABLED
+  #include "stm32f3xx_hal_dma.h"
+#endif /* HAL_DMA_MODULE_ENABLED */
+   
+#ifdef HAL_CORTEX_MODULE_ENABLED
+ #include "stm32f3xx_hal_cortex.h"
+#endif /* HAL_CORTEX_MODULE_ENABLED */
+
+#ifdef HAL_ADC_MODULE_ENABLED
+ #include "stm32f3xx_hal_adc.h"
+#endif /* HAL_ADC_MODULE_ENABLED */
+
+#ifdef HAL_CAN_MODULE_ENABLED
+ #include "stm32f3xx_hal_can.h"
+#endif /* HAL_CAN_MODULE_ENABLED */
+
+#ifdef HAL_CAN_LEGACY_MODULE_ENABLED
+ #include "stm32f3xx_hal_can_legacy.h"
+#endif /* HAL_CAN_LEGACY_MODULE_ENABLED */
+
+#ifdef HAL_CEC_MODULE_ENABLED
+ #include "stm32f3xx_hal_cec.h"
+#endif /* HAL_CEC_MODULE_ENABLED */
+
+#ifdef HAL_COMP_MODULE_ENABLED
+ #include "stm32f3xx_hal_comp.h"
+#endif /* HAL_COMP_MODULE_ENABLED */
+
+#ifdef HAL_CRC_MODULE_ENABLED
+ #include "stm32f3xx_hal_crc.h"
+#endif /* HAL_CRC_MODULE_ENABLED */
+
+#ifdef HAL_DAC_MODULE_ENABLED
+ #include "stm32f3xx_hal_dac.h"
+#endif /* HAL_DAC_MODULE_ENABLED */
+
+#ifdef HAL_FLASH_MODULE_ENABLED
+ #include "stm32f3xx_hal_flash.h"
+#endif /* HAL_FLASH_MODULE_ENABLED */
+
+#ifdef HAL_HRTIM_MODULE_ENABLED
+ #include "stm32f3xx_hal_hrtim.h"
+#endif /* HAL_HRTIM_MODULE_ENABLED */
+
+#ifdef HAL_I2C_MODULE_ENABLED
+ #include "stm32f3xx_hal_i2c.h"
+#endif /* HAL_I2C_MODULE_ENABLED */
+
+#ifdef HAL_I2S_MODULE_ENABLED
+ #include "stm32f3xx_hal_i2s.h"
+#endif /* HAL_I2S_MODULE_ENABLED */
+
+#ifdef HAL_IRDA_MODULE_ENABLED
+ #include "stm32f3xx_hal_irda.h"
+#endif /* HAL_IRDA_MODULE_ENABLED */
+
+#ifdef HAL_IWDG_MODULE_ENABLED
+ #include "stm32f3xx_hal_iwdg.h"
+#endif /* HAL_IWDG_MODULE_ENABLED */
+
+#ifdef HAL_OPAMP_MODULE_ENABLED
+ #include "stm32f3xx_hal_opamp.h"
+#endif /* HAL_OPAMP_MODULE_ENABLED */
+
+#ifdef HAL_PCD_MODULE_ENABLED
+ #include "stm32f3xx_hal_pcd.h"
+#endif /* HAL_PCD_MODULE_ENABLED */
+
+#ifdef HAL_PWR_MODULE_ENABLED
+ #include "stm32f3xx_hal_pwr.h"
+#endif /* HAL_PWR_MODULE_ENABLED */
+
+#ifdef HAL_RTC_MODULE_ENABLED
+ #include "stm32f3xx_hal_rtc.h"
+#endif /* HAL_RTC_MODULE_ENABLED */
+
+#ifdef HAL_SDADC_MODULE_ENABLED
+ #include "stm32f3xx_hal_sdadc.h"
+#endif /* HAL_SDADC_MODULE_ENABLED */
+
+#ifdef HAL_SMARTCARD_MODULE_ENABLED
+ #include "stm32f3xx_hal_smartcard.h"
+#endif /* HAL_SMARTCARD_MODULE_ENABLED */
+
+#ifdef HAL_SMBUS_MODULE_ENABLED
+ #include "stm32f3xx_hal_smbus.h"
+#endif /* HAL_SMBUS_MODULE_ENABLED */
+
+#ifdef HAL_SPI_MODULE_ENABLED
+ #include "stm32f3xx_hal_spi.h"
+#endif /* HAL_SPI_MODULE_ENABLED */
+
+#ifdef HAL_TIM_MODULE_ENABLED
+ #include "stm32f3xx_hal_tim.h"
+#endif /* HAL_TIM_MODULE_ENABLED */
+
+#ifdef HAL_TSC_MODULE_ENABLED
+ #include "stm32f3xx_hal_tsc.h"
+#endif /* HAL_TSC_MODULE_ENABLED */
+
+#ifdef HAL_UART_MODULE_ENABLED
+ #include "stm32f3xx_hal_uart.h"
+#endif /* HAL_UART_MODULE_ENABLED */
+
+#ifdef HAL_USART_MODULE_ENABLED
+ #include "stm32f3xx_hal_usart.h"
+#endif /* HAL_USART_MODULE_ENABLED */
+
+#ifdef HAL_WWDG_MODULE_ENABLED
+ #include "stm32f3xx_hal_wwdg.h"
+#endif /* HAL_WWDG_MODULE_ENABLED */
+
+/* Exported macro ------------------------------------------------------------*/
+#ifdef  USE_FULL_ASSERT
+/**
+  * @brief  The assert_param macro is used for function's parameters check.
+  * @param  expr: If expr is false, it calls assert_failed function
+  *         which reports the name of the source file and the source
+  *         line number of the call that failed. 
+  *         If expr is true, it returns no value.
+  * @retval None
+  */
+  #define assert_param(expr) ((expr) ? (void)0U : assert_failed((uint8_t *)__FILE__, __LINE__))
+/* Exported functions ------------------------------------------------------- */
+  void assert_failed(uint8_t* file, uint32_t line);
+#else
+  #define assert_param(expr) ((void)0U)
+#endif /* USE_FULL_ASSERT */    
+    
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __STM32F3xx_HAL_CONF_H */
+
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
diff --git a/lib/cmsis_core b/lib/cmsis_core
new file mode 160000
+Subproject 96d6da4e252b06dcfdc041e7df23e86161c3300
diff --git a/lib/cmsis_device b/lib/cmsis_device
new file mode 160000
+Subproject 5e4ee5ed7a7b6c85176bb70a9fd3c72d6eb99f1
diff --git a/lib/hal_driver b/lib/hal_driver
new file mode 160000
+Subproject 1761b6207318ede021706e75aae78f452d72b6f
diff --git a/lib/musl b/lib/musl
new file mode 160000
+Subproject a5aff1972c9e3981566414b09a28e331ccd2be5
diff --git a/src/bootloader.c b/src/bootloader.c
new file mode 100644
index 0000000..f6e313a
--- /dev/null
+++ b/src/bootloader.c
@@ -0,0 +1,99 @@
+
+#include <fe_global.h>
+#include <fe_config_backend.h>
+#include <bootloader.h>
+#include <core_cm4.h>
+
+typedef void (*void_func)(void);
+
+extern int _Flash_Base;
+size_t flash_base = (size_t)&_Flash_Base;
+extern int _Flash_Size;
+size_t flash_size = (size_t)&_Flash_Size;
+extern int _Bootloader_Size;
+size_t bootloader_size = (size_t)&_Bootloader_Size;
+
+
+bool fe_check_img_valid(void) {
+    uint32_t *end_of_flash = (uint32_t *)(flash_base + flash_size);
+    end_of_flash -= 1;
+    return *end_of_flash != 0xffffffff;
+}
+
+void fe_jump_to_application() {
+    uint32_t *user_isr_vector = (uint32_t *)flash_base;
+    void_func user_reset_vector = (void_func)user_isr_vector[1];
+
+    SCB->VTOR = (uint32_t)flash_base;
+    __set_MSP(user_isr_vector[0]);
+    user_reset_vector();
+}
+
+void fe_system_reset(void) {
+    SCB->AIRCR |= SCB_AIRCR_SYSRESETREQ_Msk;
+}
+
+void flash_unlock() {
+    FLASH->KEYR = 0x45670123;
+    FLASH->KEYR = 0xCDEF89AB;
+}
+
+void flash_lock() {
+    FLASH->CR |= FLASH_CR_LOCK;
+}
+
+int flash_erase_page(size_t addr) {
+    while (FLASH->SR & FLASH_SR_BSY)
+        ;
+
+    FLASH->CR |= FLASH_CR_PER;
+    FLASH->AR = addr;
+    FLASH->CR |= FLASH_CR_STRT;
+
+    /* RM0365, pg. 63: The software should start checking if the BSY bit equals ‘0’ at least one CPU cycle after setting
+     * the STRT bit */
+    asm volatile ("nop");
+
+    while (FLASH->SR & FLASH_SR_BSY)
+        ;
+
+    if (FLASH->SR & FLASH_SR_EOP) {
+        FLASH->SR = FLASH_SR_EOP;
+        return 0;
+    }
+    return -1;
+}
+
+int flash_write(size_t addr, char *buf, size_t len) {
+    assert((len&1) == 0);
+    assert((addr&1) == 0);
+
+    uint16_t *dst = (uint16_t *)addr;
+    uint16_t *src = (uint16_t *)src;
+    len /= 2;
+    while (len--) {
+        *dst++ = *src++;
+        while (FLASH->SR & FLASH_SR_BSY)
+            ;
+    }
+
+    if (FLASH->SR & FLASH_SR_EOP)
+        FLASH->SR = FLASH_SR_EOP;
+    else
+        return 1;
+
+    return 0;
+}
+
+int erase_user_flash() {
+    assert ((_Bootloader_Size & (PAGE_SIZE-1)) == 0);
+    size_t first_page = _Flash_Base + _Bootloader_Size;
+    size_t npages = (_Flash_Size - _Bootloader_Size) / PAGE_SIZE;
+
+    int rc = 0;
+    while (npages--)
+        rc |= flash_erase_page(first_page + npages); /* TODO error handling */
+    return rc;
+}
+
+
diff --git a/src/clocks.c b/src/clocks.c
new file mode 100644
index 0000000..a8cb8e4
--- /dev/null
+++ b/src/clocks.c
@@ -0,0 +1,83 @@
+#include <fe_global.h>
+#include <fe_clocks.h>
+
+unsigned int sysclk_speed;
+unsigned int ahb_speed;
+unsigned int apb1_speed;
+unsigned int apb2_speed;
+unsigned int apb1_timer_speed;
+unsigned int apb2_timer_speed;
+
+
+void delay_ms(int ms) {
+    uint32_t init_val = SysTick->VAL;
+    uint32_t wait_end = sys_time_millis + ms;
+
+    while (sys_time_millis < wait_end)
+        ;
+
+    while (SysTick->VAL >= init_val) {
+        if (sys_time_millis > wait_end)
+            return;
+    }
+}
+
+void fe_config_clocks()
+{
+    /* 8MHz HSI clock as PLL source. */
+#define HSI_SPEED 8000000
+    /* PLL output = HSI / 2 * PLL_MUL */
+#define PLL_MUL 16
+
+    /* Check that we came out of reset correctly */
+    if (((RCC->CFGR & RCC_CFGR_SWS_Msk) >> RCC_CFGR_SW_Pos) != 0)
+        asm volatile ("bkpt");
+    if (RCC->CR & RCC_CR_HSEON)
+        asm volatile ("bkpt");
+    if (RCC->CR & RCC_CR_PLLON)
+        asm volatile ("bkpt");
+
+    RCC->CFGR = 0;
+    RCC->CFGR |= (0<<RCC_CFGR_PLLSRC_Pos); /* PLL input: HSI /2 */
+    RCC->CFGR |= ((PLL_MUL-2)<<RCC_CFGR_PLLMUL_Pos);
+    sysclk_speed = HSI_SPEED / 2 * PLL_MUL;
+
+    /* set AHB prescaler to /1 */
+    RCC->CFGR |= (0 << RCC_CFGR_HPRE_Pos);
+    ahb_speed = sysclk_speed;
+
+    /* set ABP1 prescaler to 2 -> 36MHz */
+    RCC->CFGR |= (4 << RCC_CFGR_PPRE1_Pos);
+    apb1_speed = sysclk_speed / 2;
+    apb1_timer_speed = apb1_speed * 2;
+
+    /* set ABP2 prescaler to 2 -> 36MHz */
+    RCC->CFGR |= (4 << RCC_CFGR_PPRE2_Pos);
+    apb2_speed = sysclk_speed / 2;
+    apb2_timer_speed = apb2_speed * 2;
+
+    /* Configure PLL */
+    RCC->CR |= RCC_CR_PLLON;
+
+    /* Wait for main PLL */
+    while(!(RCC->CR & RCC_CR_PLLRDY))
+        ;
+
+    /* Configure Flash: enable prefetch; set latency = 2 wait states
+     * See reference manual (RM0365), Section 4.5.1
+     */
+    FLASH->ACR = FLASH_ACR_PRFTBE | (2<<FLASH_ACR_LATENCY_Pos);
+
+    /* Select PLL as system clock source */
+    RCC->CFGR &= ~RCC_CFGR_SW_Msk;
+    RCC->CFGR |= 2 << RCC_CFGR_SW_Pos;
+
+    /* Wait for clock to switch over */
+    while ((RCC->CFGR & RCC_CFGR_SWS_Msk)>>RCC_CFGR_SWS_Pos != 2)
+        ;
+
+    SystemCoreClockUpdate();
+    SysTick_Config(SystemCoreClock / 1000); /* 1 ms ticks */
+
+    NVIC_SetPriority(SysTick_IRQn, 32);
+}
diff --git a/src/cobs.c b/src/cobs.c
new file mode 100644
index 0000000..f6fb84a
--- /dev/null
+++ b/src/cobs.c
@@ -0,0 +1,211 @@
+
+#include "cobs.h"
+
+int cobs_encode_usart(int (*output)(void*, char), void *userdata, char *src, size_t srclen) {
+    if (srclen > 254)
+        return -1;
+
+    size_t p = 0;
+    while (p <= srclen) {
+
+        char val;
+        if (p != 0 && src[p-1] != 0) {
+            val = src[p-1];
+
+        } else {
+            size_t q = p;
+            while (q < srclen && src[q] != 0)
+                q++;
+            val = (char)q-p+1;
+        }
+
+        int rv = output(userdata, val);
+        if (rv)
+            return rv;
+        p++;
+    }
+
+    int rv = output(userdata, 0);
+    if (rv)
+        return rv;
+
+    return 0;
+}
+
+/*@ requires \valid(dst + (0..dstlen-1));
+  @ requires \valid_read(src + (0..srclen-1));
+  @ requires \separated(dst + (0..dstlen-1), src + (0..srclen-1));
+  @ 
+  @ behavior maybe_valid_frame:
+  @     assumes 1 <= srclen <= dstlen <= 65535;
+  @     assumes \exists integer j; j > 0 && \forall integer i; 0 <= i < j ==> src[i] != 0;
+  @     assumes \exists integer i; 0 <= i < srclen && src[i] == 0;
+  @     assigns dst[0..dstlen-1];
+  @     ensures \result >= 0 || \result == -3;
+  @     ensures \result >= 0 ==> src[\result+1] == 0;
+  @     ensures \result >= 0 ==> (\forall integer i; 0 <= i < \result ==> src[i] != 0);
+  @
+  @ behavior invalid_frame:
+  @     assumes 1 <= srclen <= dstlen <= 65535;
+  @     assumes src[0] == 0 || \forall integer i; 0 <= i < srclen ==> src[i] != 0;
+  @     assigns dst[0..dstlen-1];
+  @     ensures \result == -2;
+  @
+  @ behavior invalid_buffers:
+  @     assumes    dstlen < 0 || dstlen > 65535
+  @             || srclen < 1 || srclen > 65535
+  @             || dstlen < srclen;
+  @     assigns \nothing;
+  @     ensures \result == -1;
+  @
+  @ complete behaviors;
+  @ disjoint behaviors;
+  @*/
+ssize_t cobs_decode(char *dst, size_t dstlen, char *src, size_t srclen) {
+    if (dstlen > 65535 || srclen > 65535)
+        return -1;
+
+    if (srclen < 1)
+        return -1;
+
+    if (dstlen < srclen)
+        return -1;
+
+    size_t p = 1;
+    size_t c = (unsigned char)src[0];
+    //@ assert 0 <= c < 256;
+    //@ assert 0 <= c;
+    //@ assert c < 256;
+    if (c == 0)
+        return -2; /* invalid framing. An empty frame would be [...] 00 01 00, not [...] 00 00 */
+    //@ assert c >= 0;
+    //@ assert c != 0;
+    //@ assert c <= 257;
+    //@ assert c > 0;
+    //@ assert c >= 0 && c != 0 ==> c > 0;
+
+    /*@ //loop invariant \forall integer i; 0 <= i <= p ==> (i == srclen || src[i] != 0);
+      @ loop invariant \forall integer i; 1 <= i < p ==> src[i] != 0;
+      @ loop invariant c > 0;
+      @ loop invariant 1 <= p <= srclen <= dstlen <= 65535;
+      @ loop invariant \separated(dst + (0..dstlen-1), src + (0..srclen-1));
+      @ loop invariant \valid_read(src + (0..srclen-1));
+      @ loop invariant \forall integer i; 1 <= i <= srclen ==> \valid(dst + i - 1);
+      @ loop assigns dst[0..dstlen-1], p, c;
+      @ loop variant srclen-p;
+      @*/
+    while (p < srclen && src[p]) {
+        char val;
+        c--;
+
+        //@ assert src[p] != 0;
+        if (c == 0) {
+            c = (unsigned char)src[p];
+            val = 0;
+        } else {
+            val = src[p];
+        }
+
+        //@ assert 0 <= p-1 <= dstlen-1;
+        dst[p-1] = val;
+        p++;
+    }
+
+    if (p == srclen)
+        return -2; /* Invalid framing. The terminating null byte should always be present in the input buffer. */
+
+    if (c != 1)
+        return -3; /* Invalid framing. The skip counter does not hit the end of the frame. */
+
+    //@ assert 0 < p <= srclen <= 65535;
+    //@ assert src[p] == 0;
+    //@ assert \forall integer i; 1 <= i < p ==> src[i] != 0;
+    return p-1;
+}
+
+void cobs_decode_incremental_initialize(struct cobs_decode_state *state) {
+    state->p = 0;
+    state->c = 0;
+}
+
+int cobs_decode_incremental(struct cobs_decode_state *state, char *dst, size_t dstlen, char src) {
+    if (state->p == 0) {
+        if (src == 0)
+            goto empty_errout; /* invalid framing. An empty frame would be [...] 00 01 00, not [...] 00 00 */
+        state->c = (unsigned char)src;
+        state->p++;
+        return -1;
+    }
+
+    if (!src) {
+        if (state->c != 1)
+            goto errout; /* Invalid framing. The skip counter does not hit the end of the frame. */
+        int rv = state->p-1;
+        cobs_decode_incremental_initialize(state);
+        return rv;
+    }
+
+    char val;
+    state->c--;
+
+    if (state->c == 0) {
+        state->c = (unsigned char)src;
+        val = 0;
+    } else {
+        val = src;
+    }
+
+    size_t pos = state->p-1;
+    if (pos >= dstlen)
+        return -4; /* output buffer too small */
+    dst[pos] = val;
+    state->p++;
+    return -1;
+
+errout:
+    cobs_decode_incremental_initialize(state);
+    return -2;
+
+empty_errout:
+    cobs_decode_incremental_initialize(state);
+    return -3;
+}
+
+#ifdef VALIDATION
+/*@ 
+  @ requires 0 <= d < 256;
+  @ assigns \nothing;
+  @*/
+size_t test(char foo, unsigned int d) {
+    unsigned int c = (unsigned char)foo;
+    if (c != 0) {
+        //@ assert c < 256;
+        //@ assert c >= 0;
+        //@ assert c != 0;
+        //@ assert c > 0;
+    }
+    if (d != 0) {
+        //@ assert d >= 0;
+        //@ assert d != 0;
+        //@ assert d > 0;
+    }
+    return c + d;
+}
+
+#include <__fc_builtin.h>
+
+void main(void) {
+    char inbuf[254];
+    char cobsbuf[256];
+    char outbuf[256];
+
+    size_t range = Frama_C_interval(0, sizeof(inbuf));
+    Frama_C_make_unknown((char *)inbuf, range);
+
+    cobs_encode(cobsbuf, sizeof(cobsbuf), inbuf, sizeof(inbuf));
+    cobs_decode(outbuf, sizeof(outbuf), cobsbuf, sizeof(cobsbuf));
+    
+    //@ assert \forall integer i; 0 <= i < sizeof(inbuf) ==> outbuf[i] == inbuf[i];
+}
+#endif//VALIDATION
+
diff --git a/src/interrupts.c b/src/interrupts.c
new file mode 100644
index 0000000..00ee749
--- /dev/null
+++ b/src/interrupts.c
@@ -0,0 +1,62 @@
+#include "fe_global.h"
+#include "fe_interrupts.h"
+   
+uint64_t sys_time_millis;
+
+/******************************************************************************/
+/* Cortex-M4 CPU Interrupts                                                   */
+/******************************************************************************/
+
+void NMI_Handler(void)
+{
+}
+
+void HardFault_Handler(void)
+{
+    while (42) {
+        asm volatile ("bkpt #13");
+    }
+}
+
+void MemManage_Handler(void)
+{
+    while (42) {
+        asm volatile ("bkpt #12");
+    }
+}
+
+void BusFault_Handler(void)
+{
+    while (42) {
+        asm volatile ("bkpt #11");
+    }
+}
+
+void UsageFault_Handler(void)
+{
+    while (42) {
+        asm volatile ("bkpt #10");
+    }
+}
+
+void SVC_Handler(void)
+{
+}
+
+void DebugMon_Handler(void)
+{
+}
+
+void PendSV_Handler(void)
+{
+}
+
+void SysTick_Handler(void)
+{
+    sys_time_millis += 1;
+}
+
+/******************************************************************************/
+/* STM32 Peripheral interrupts                                                */
+/******************************************************************************/
+
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..f9992f5
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,370 @@
+#include <fe_global.h>
+#include <fe_clocks.h>
+#include <bootloader.h>
+#include <cobs.h>
+
+/* User configuration */
+#include <fe_config_backend.h>
+
+struct usart_config {
+    uint32_t rx_rcc_ahbenr_flags;
+    GPIO_TypeDef *rx_gpio;
+    int rx_pin;
+    int rx_alt;
+
+    uint32_t tx_rcc_ahbenr_flags;
+    GPIO_TypeDef *tx_gpio;
+    int tx_pin;
+    int tx_alt;
+
+    uint32_t apb1enr_mask;
+    uint32_t apb2enr_mask;
+    USART_TypeDef *usart;
+};
+
+struct usart_config usart_gpios[FE_CONFIG_USART_COUNT] = {
+    [FE_CONFIG_USART1_PB7] = {FE_CONFIG_GPIOB, 7, 7, FE_CONFIG_GPIOB, 6, 7, 0, RCC_APB2ENR_USART1EN, USART1},
+};
+
+void run_bootloader(void);
+int bootloader_handle_cmd(USART_TypeDef *us, char *buf, size_t len);
+void usart_init(struct usart_config *uc);
+void usart_putc(USART_TypeDef *us, char c);
+void usart_puts(USART_TypeDef *us, const char *data);
+int usart_rx(USART_TypeDef *us);
+int usart_tx_framed(USART_TypeDef * us, char *buf, size_t len);
+
+void __libc_init_array(void) { /* we don't need this. */ }
+
+void __assert_func (unused_a const char *file, unused_a int line, unused_a const char *function, unused_a const char *expr) {
+    asm volatile ("bkpt #69");
+    while(1) {}
+}
+
+void gpio_config(GPIO_TypeDef *gpio, int pin, int mode, int speed, int pullups, int alt) {
+    gpio->MODER &= ~(3<<(2*pin));
+    gpio->MODER |= mode<<(2*pin);
+    gpio->OSPEEDR &= ~(3<<(2*pin));
+    gpio->OSPEEDR |= speed<<(2*pin);
+    gpio->PUPDR &= ~(3<<(2*pin));
+    gpio->PUPDR |= pullups<<(2*pin);
+    if (pin < 8) {
+        gpio->AFR[0] &= ~(0xf << (4*pin));
+        gpio->AFR[0] |= alt << (4*pin);
+    } else {
+        pin -= 8;
+        gpio->AFR[1] &= ~(0xf << (4*pin));
+        gpio->AFR[1] |= alt << (4*pin);
+    }
+}
+
+int main(void)
+{
+    const struct fe_config_def *c = &fe_config;
+
+    uint32_t old_moder = c->bootloader_enable_pin.gpio->MODER;
+    uint32_t old_ospeedr = c->bootloader_enable_pin.gpio->OSPEEDR;
+    uint32_t old_pupdr = c->bootloader_enable_pin.gpio->PUPDR;
+    RCC->AHBENR |= c->bootloader_enable_pin.rcc_ahbenr_flags;
+    int pullups = c->bootloader_enable_level ? 2 : 1;
+    gpio_config(c->bootloader_enable_pin.gpio, c->bootloader_enable_pin.pin_number, 0, 0, pullups, 0);
+
+    delay_ms(50);
+    int enable_pin_state = ((c->bootloader_enable_pin.gpio->IDR >> c->bootloader_enable_pin.pin_number) & 1);
+    if (enable_pin_state == c->bootloader_enable_level || !fe_check_img_valid()) {
+        fe_config_clocks();
+        run_bootloader();
+        fe_system_reset();
+
+    } else {
+        c->bootloader_enable_pin.gpio->MODER = old_moder;
+        c->bootloader_enable_pin.gpio->OSPEEDR = old_ospeedr;
+        c->bootloader_enable_pin.gpio->PUPDR = old_pupdr;
+        fe_jump_to_application();
+    }
+
+    /* Should never be reached. */
+    assert(0);
+    return 0;
+}
+
+#define MAX_RX_SIZE 512
+char rx_buf[MAX_RX_SIZE];
+
+void run_bootloader() {
+    assert(fe_config.usart <= FE_CONFIG_USART_COUNT);
+    struct usart_config *uc = &usart_gpios[fe_config.usart];
+
+    usart_init(uc);
+    usart_puts(uc->usart, fe_config.welcome_string);
+    usart_putc(uc->usart, 0x00);
+
+    struct cobs_decode_state cobs_st;
+    cobs_decode_incremental_initialize(&cobs_st);
+    while (42) {
+        int c = usart_rx(uc->usart);
+        if (c == -2) {
+            /* ignore errors for now */
+            continue;
+        } else if (c == -1) {
+            /* We received nothing */
+            continue;
+        }
+
+        int rc = cobs_decode_incremental(&cobs_st, rx_buf, sizeof(rx_buf), c);
+        if (rc == -1) {
+            continue;
+
+        } else if (rc < 0) {
+            /* Ignore errors for now */
+            continue;
+        }
+
+        (void)bootloader_handle_cmd(uc->usart, rx_buf, rc); /* ignore errors for now */
+    }
+}
+
+enum bootloader_cmd {
+    /* Generic commands */
+    FE_CMD_REPLY = 0,
+    FE_CMD_PING = 1,
+    FE_CMD_IDENTIFY = 2,
+
+    /* Bootloader commands */
+    FE_CMD_ERASE = 16 + 0,
+    FE_CMD_WRITE_BLOCK = 16 + 1,
+    FE_CMD_REBOOT = 16 + 2,
+
+    /* Reserved commands */
+    FE_CMD_RESERVED0 = 'e', /* 0x65 / 101 Reserved for welcome string */
+};
+
+enum error_codes {
+    FE_SUCCESS = 0,
+    FE_ECMD = 1,
+    FE_ESIZE = 2,
+    FE_EINVAL = 3,
+    FE_ESYS = 4,
+};
+
+#define FE_MAX_PACKET_SIZE 254
+struct cmd_header {
+    uint8_t cmd; /* Command code, see enum bootloader_cmd */
+    uint32_t tag; /* Tag for request/response identification. Echoed back to requestor in response. */
+} __attribute__((packed));
+
+#define FE_MAX_PAYLOAD_SIZE (FE_MAX_PACKET_SIZE - sizeof(struct cmd_header))
+
+struct id_response {
+    uint8_t major_version;
+    uint8_t minor_version;
+    uint32_t idcode;
+    uint8_t serial[6];
+    char id_string[FE_MAX_PAYLOAD_SIZE - 2];
+};
+
+struct simple_response {
+    int32_t return_code;
+};
+
+struct cmd_packet {
+    struct cmd_header hdr;
+    union {
+        uint8_t data[FE_MAX_PAYLOAD_SIZE];
+        struct id_response id_response;
+        struct simple_response simple_response;
+    };
+};
+
+static const uint8_t major_version = 1;
+static const uint8_t minor_version = 0;
+static const char *id_string = "Fenris Bootloader";
+
+static int err_simple(USART_TypeDef *us, struct cmd_packet *pkt, int rc);
+static int err_simple(USART_TypeDef *us, struct cmd_packet *pkt, int rc) {
+    struct simple_response *res = &pkt->simple_response;
+    pkt->hdr.cmd = FE_CMD_REPLY;
+    /* leave tag unaffected */
+    res->return_code = rc;
+    return usart_tx_framed(us, (char *)pkt, sizeof(struct cmd_header) + sizeof(struct simple_response));
+}
+
+static size_t flash_write_addr = 0;
+
+int bootloader_handle_cmd(USART_TypeDef *us, char *buf, size_t len) {
+    struct cmd_packet *pkt = (struct cmd_packet *)buf;
+    int rc = 0;
+    if (len < sizeof(struct cmd_header)) {
+        memset(buf, 0, sizeof(struct cmd_header));
+        return err_simple(us, pkt, -FE_ESIZE);
+    }
+    int payload_len = len-sizeof(struct cmd_header);
+
+    pkt->hdr.cmd = FE_CMD_REPLY;
+
+    switch (pkt->hdr.cmd) {
+        case FE_CMD_PING:
+            return usart_tx_framed(us, buf, len);
+
+        case FE_CMD_IDENTIFY: {
+            if (payload_len != 0)
+                return err_simple(us, pkt, -FE_ESIZE);
+
+            struct id_response *res = &pkt->id_response;
+            memcpy(res->serial, (void*)UID_BASE, 12);
+            res->idcode = DBGMCU->IDCODE;
+            res->major_version = major_version;
+            res->minor_version = minor_version;
+            strncpy(res->id_string, id_string, sizeof(res->id_string));
+            len = sizeof(struct cmd_header) + 2 + strlen(id_string) + 1;
+            if (len < FE_MAX_PACKET_SIZE)
+                return usart_tx_framed(us, buf, len);
+            return -10;
+        }
+
+        case FE_CMD_ERASE: {
+            if (payload_len != 4)
+                return err_simple(us, pkt, -FE_ESIZE);
+
+            if (*((uint32_t*)pkt->data) != 0x54454c44)
+                return err_simple(us, pkt, -FE_EINVAL);
+            
+            flash_unlock();
+
+            if (erase_user_flash()) {
+                flash_lock();
+                return err_simple(us, pkt, -FE_ESYS);
+            }
+
+            flash_lock();
+            flash_write_addr = flash_base;
+
+            return err_simple(us, pkt, 0);
+        }
+
+        case FE_CMD_WRITE_BLOCK: {
+            if (payload_len == 0)
+                return err_simple(us, pkt, -FE_ESIZE);
+
+            if ((payload_len&1) != 0)
+                return err_simple(us, pkt, -FE_ESIZE);
+            
+            if (flash_write_addr + payload_len == flash_size) {
+                /* FIXME sig check */
+                if (0) { /* invalid signature */
+                    return err_simple(us, pkt, -FE_EINVAL);
+                }
+
+            } else if (flash_write_addr + payload_len > flash_size) {
+                return err_simple(us, pkt, -FE_EINVAL);
+            }
+
+            if (!flash_write(flash_write_addr, pkt->data, payload_len))
+                return err_simple(us, pkt, -FE_ESYS);
+            flash_write_addr += payload_len;
+        }
+        case FE_CMD_REBOOT: {
+            fe_system_reset();
+        }
+
+        default: {
+            return err_simple(us, pkt, -FE_ECMD);
+        }
+    }
+}
+
+void usart_init(struct usart_config *uc) {
+    RCC->AHBENR |= uc->rx_rcc_ahbenr_flags | uc->tx_rcc_ahbenr_flags;
+    gpio_config(uc->rx_gpio, uc->rx_pin, 2, 3, 1, uc->rx_alt);
+    gpio_config(uc->tx_gpio, uc->tx_pin, 2, 3, 0, uc->tx_alt);
+    
+    RCC->APB1ENR |= uc->apb1enr_mask;
+    RCC->APB2ENR |= uc->apb2enr_mask;
+
+    uc->usart->CR1 = USART_CR1_TE | USART_CR1_RE;
+    
+    int bus_speed = uc->apb1enr_mask ? apb1_speed : apb2_speed;
+    uc->usart->BRR = bus_speed * 16 / fe_config.baudrate / 16;
+    uc->usart->CR1 |= USART_CR1_UE;
+}
+
+void usart_putc(USART_TypeDef *us, char c) {
+    while (!(us->ISR & USART_ISR_TXE))
+        ;
+    us->TDR = c;
+}
+
+void usart_puts(USART_TypeDef *us, const char *data) {
+    for (const char *c = data; *c; c++)
+        usart_putc(us, *c);
+}
+
+int usart_rx(USART_TypeDef *us) {
+    if ((us->ISR & USART_ISR_ORE) || (us->ISR & USART_ISR_PE)) {
+        /* Ignore overruns or parity errors */
+        us->ICR = USART_ICR_ORECF | USART_ICR_PECF;
+        return -2;
+    }
+
+    if (us->ISR & USART_ISR_RXNE)
+        return us->RDR;
+
+    return -1;
+}
+
+static int cobs_encode_usart_output(void *userdata, char c);
+static int cobs_encode_usart_output(void *userdata, char c) {
+    usart_putc((USART_TypeDef *)userdata, c);
+    return 0;
+}
+
+int usart_tx_framed(USART_TypeDef * us, char *buf, size_t len) {
+    return cobs_encode_usart(cobs_encode_usart_output, us, buf, len);
+}
+
+void *memcpy(void *restrict dest, const void *restrict src, size_t n)
+{
+	unsigned char *d = dest;
+	const unsigned char *s = src;
+
+	for (; n; n--) *d++ = *s++;
+	return dest;
+}
+
+void *memset(void *dest, int c, size_t n)
+{
+	unsigned char *s = dest;
+	size_t k;
+
+	/* Fill head and tail with minimal branching. Each
+	 * conditional ensures that all the subsequently used
+	 * offsets are well-defined and in the dest region. */
+
+	if (!n) return dest;
+	s[0] = c;
+	s[n-1] = c;
+	if (n <= 2) return dest;
+	s[1] = c;
+	s[2] = c;
+	s[n-2] = c;
+	s[n-3] = c;
+	if (n <= 6) return dest;
+	s[3] = c;
+	s[n-4] = c;
+	if (n <= 8) return dest;
+
+	/* Advance pointer to align it at a 4-byte boundary,
+	 * and truncate n to a multiple of 4. The previous code
+	 * already took care of any head/tail that get cut off
+	 * by the alignment. */
+
+	k = -(uintptr_t)s & 3;
+	s += k;
+	n -= k;
+	n &= -4;
+
+	/* Pure C fallback with no aliasing violations. */
+	for (; n; n--, s++) *s = c;
+
+	return dest;
+}
diff --git a/src/system_stm32f3xx.c b/src/system_stm32f3xx.c
new file mode 100644
index 0000000..9e75a9e
--- /dev/null
+++ b/src/system_stm32f3xx.c
@@ -0,0 +1,298 @@
+/**
+  ******************************************************************************
+  * @file    system_stm32f3xx.c
+  * @author  MCD Application Team
+  * @brief   CMSIS Cortex-M4 Device Peripheral Access Layer System Source File.
+  *
+  * 1. This file provides two functions and one global variable to be called from
+  *    user application:
+  *      - SystemInit(): This function is called at startup just after reset and 
+  *                      before branch to main program. This call is made inside
+  *                      the "startup_stm32f3xx.s" file.
+  *
+  *      - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
+  *                                  by the user application to setup the SysTick
+  *                                  timer or configure other parameters.
+  *
+  *      - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
+  *                                 be called whenever the core clock is changed
+  *                                 during program execution.
+  *
+  * 2. After each device reset the HSI (8 MHz) is used as system clock source.
+  *    Then SystemInit() function is called, in "startup_stm32f3xx.s" file, to
+  *    configure the system clock before to branch to main program.
+  *
+  * 3. This file configures the system clock as follows:
+  *=============================================================================
+  *                         Supported STM32F3xx device
+  *-----------------------------------------------------------------------------
+  *        System Clock source                    | HSI
+  *-----------------------------------------------------------------------------
+  *        SYSCLK(Hz)                             | 8000000
+  *-----------------------------------------------------------------------------
+  *        HCLK(Hz)                               | 8000000
+  *-----------------------------------------------------------------------------
+  *        AHB Prescaler                          | 1
+  *-----------------------------------------------------------------------------
+  *        APB2 Prescaler                         | 1
+  *-----------------------------------------------------------------------------
+  *        APB1 Prescaler                         | 1
+  *-----------------------------------------------------------------------------
+  *        USB Clock                              | DISABLE
+  *-----------------------------------------------------------------------------
+  *=============================================================================
+  ******************************************************************************
+  * @attention
+  *
+  * <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
+  * All rights reserved.</center></h2>
+  *
+  * This software component is licensed by ST under BSD 3-Clause license,
+  * the "License"; You may not use this file except in compliance with the
+  * License. You may obtain a copy of the License at:
+  *                        opensource.org/licenses/BSD-3-Clause
+  *
+  ******************************************************************************
+  */
+
+/** @addtogroup CMSIS
+  * @{
+  */
+
+/** @addtogroup stm32f3xx_system
+  * @{
+  */
+
+/** @addtogroup STM32F3xx_System_Private_Includes
+  * @{
+  */
+
+#include "stm32f3xx.h"
+
+/**
+  * @}
+  */
+
+/** @addtogroup STM32F3xx_System_Private_TypesDefinitions
+  * @{
+  */
+
+/**
+  * @}
+  */
+
+/** @addtogroup STM32F3xx_System_Private_Defines
+  * @{
+  */
+#if !defined  (HSE_VALUE) 
+  #define HSE_VALUE    ((uint32_t)8000000) /*!< Default value of the External oscillator in Hz.
+                                                This value can be provided and adapted by the user application. */
+#endif /* HSE_VALUE */
+
+#if !defined  (HSI_VALUE)
+  #define HSI_VALUE    ((uint32_t)8000000) /*!< Default value of the Internal oscillator in Hz.
+                                                This value can be provided and adapted by the user application. */
+#endif /* HSI_VALUE */
+
+/*!< Uncomment the following line if you need to relocate your vector Table in
+     Internal SRAM. */
+/* #define VECT_TAB_SRAM */
+#define VECT_TAB_OFFSET  0x0 /*!< Vector Table base offset field.
+                                  This value must be a multiple of 0x200. */
+/**
+  * @}
+  */
+
+/** @addtogroup STM32F3xx_System_Private_Macros
+  * @{
+  */
+
+/**
+  * @}
+  */
+
+/** @addtogroup STM32F3xx_System_Private_Variables
+  * @{
+  */
+  /* This variable is updated in three ways:
+      1) by calling CMSIS function SystemCoreClockUpdate()
+      2) by calling HAL API function HAL_RCC_GetHCLKFreq()
+      3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
+         Note: If you use this function to configure the system clock there is no need to
+               call the 2 first functions listed above, since SystemCoreClock variable is 
+               updated automatically.
+  */
+uint32_t SystemCoreClock = 8000000;
+
+const uint8_t AHBPrescTable[16] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7, 8, 9};
+const uint8_t APBPrescTable[8]  = {0, 0, 0, 0, 1, 2, 3, 4};
+
+/**
+  * @}
+  */
+
+/** @addtogroup STM32F3xx_System_Private_FunctionPrototypes
+  * @{
+  */
+
+/**
+  * @}
+  */
+
+/** @addtogroup STM32F3xx_System_Private_Functions
+  * @{
+  */
+
+/**
+  * @brief  Setup the microcontroller system
+  *         Initialize the FPU setting, vector table location and the PLL configuration is reset.
+  * @param  None
+  * @retval None
+  */
+void SystemInit(void)
+{
+  /* FPU settings ------------------------------------------------------------*/
+  #if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
+    SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2));  /* set CP10 and CP11 Full Access */
+  #endif
+
+  /* Reset the RCC clock configuration to the default reset state ------------*/
+  /* Set HSION bit */
+  RCC->CR |= (uint32_t)0x00000001;
+
+  /* Reset CFGR register */
+  RCC->CFGR &= 0xF87FC00C;
+
+  /* Reset HSEON, CSSON and PLLON bits */
+  RCC->CR &= (uint32_t)0xFEF6FFFF;
+
+  /* Reset HSEBYP bit */
+  RCC->CR &= (uint32_t)0xFFFBFFFF;
+
+  /* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE bits */
+  RCC->CFGR &= (uint32_t)0xFF80FFFF;
+
+  /* Reset PREDIV1[3:0] bits */
+  RCC->CFGR2 &= (uint32_t)0xFFFFFFF0;
+
+  /* Reset USARTSW[1:0], I2CSW and TIMs bits */
+  RCC->CFGR3 &= (uint32_t)0xFF00FCCC;
+
+  /* Disable all interrupts */
+  RCC->CIR = 0x00000000;
+
+#ifdef VECT_TAB_SRAM
+  SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
+#else
+  SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
+#endif
+}
+
+/**
+   * @brief  Update SystemCoreClock variable according to Clock Register Values.
+  *         The SystemCoreClock variable contains the core clock (HCLK), it can
+  *         be used by the user application to setup the SysTick timer or configure
+  *         other parameters.
+  *
+  * @note   Each time the core clock (HCLK) changes, this function must be called
+  *         to update SystemCoreClock variable value. Otherwise, any configuration
+  *         based on this variable will be incorrect.
+  *
+  * @note   - The system frequency computed by this function is not the real
+  *           frequency in the chip. It is calculated based on the predefined
+  *           constant and the selected clock source:
+  *
+  *           - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
+  *
+  *           - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
+  *
+  *           - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**)
+  *             or HSI_VALUE(*) multiplied/divided by the PLL factors.
+  *
+  *         (*) HSI_VALUE is a constant defined in stm32f3xx_hal.h file (default value
+  *             8 MHz) but the real value may vary depending on the variations
+  *             in voltage and temperature.
+  *
+  *         (**) HSE_VALUE is a constant defined in stm32f3xx_hal.h file (default value
+  *              8 MHz), user has to ensure that HSE_VALUE is same as the real
+  *              frequency of the crystal used. Otherwise, this function may
+  *              have wrong result.
+  *
+  *         - The result of this function could be not correct when using fractional
+  *           value for HSE crystal.
+  *
+  * @param  None
+  * @retval None
+  */
+void SystemCoreClockUpdate (void)
+{
+  uint32_t tmp = 0, pllmull = 0, pllsource = 0, predivfactor = 0;
+
+  /* Get SYSCLK source -------------------------------------------------------*/
+  tmp = RCC->CFGR & RCC_CFGR_SWS;
+
+  switch (tmp)
+  {
+    case RCC_CFGR_SWS_HSI:  /* HSI used as system clock */
+      SystemCoreClock = HSI_VALUE;
+      break;
+    case RCC_CFGR_SWS_HSE:  /* HSE used as system clock */
+      SystemCoreClock = HSE_VALUE;
+      break;
+    case RCC_CFGR_SWS_PLL:  /* PLL used as system clock */
+      /* Get PLL clock source and multiplication factor ----------------------*/
+      pllmull = RCC->CFGR & RCC_CFGR_PLLMUL;
+      pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;
+      pllmull = ( pllmull >> 18) + 2;
+
+#if defined (STM32F302xE) || defined (STM32F303xE) || defined (STM32F398xx)
+        predivfactor = (RCC->CFGR2 & RCC_CFGR2_PREDIV) + 1;
+      if (pllsource == RCC_CFGR_PLLSRC_HSE_PREDIV)
+      {
+        /* HSE oscillator clock selected as PREDIV1 clock entry */
+        SystemCoreClock = (HSE_VALUE / predivfactor) * pllmull;
+      }
+      else
+      {
+        /* HSI oscillator clock selected as PREDIV1 clock entry */
+        SystemCoreClock = (HSI_VALUE / predivfactor) * pllmull;
+      }
+#else      
+      if (pllsource == RCC_CFGR_PLLSRC_HSI_DIV2)
+      {
+        /* HSI oscillator clock divided by 2 selected as PLL clock entry */
+        SystemCoreClock = (HSI_VALUE >> 1) * pllmull;
+      }
+      else
+      {
+        predivfactor = (RCC->CFGR2 & RCC_CFGR2_PREDIV) + 1;
+        /* HSE oscillator clock selected as PREDIV1 clock entry */
+        SystemCoreClock = (HSE_VALUE / predivfactor) * pllmull;
+      }
+#endif /* STM32F302xE || STM32F303xE || STM32F398xx */
+      break;
+    default: /* HSI used as system clock */
+      SystemCoreClock = HSI_VALUE;
+      break;
+  }
+  /* Compute HCLK clock frequency ----------------*/
+  /* Get HCLK prescaler */
+  tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4)];
+  /* HCLK clock frequency */
+  SystemCoreClock >>= tmp;
+}
+
+/**
+  * @}
+  */
+
+/**
+  * @}
+  */
+
+/**
+  * @}
+  */
+
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
+
diff --git a/startup_stm32f302x8.s b/startup_stm32f302x8.s
new file mode 100644
index 0000000..e91164e
--- /dev/null
+++ b/startup_stm32f302x8.s
@@ -0,0 +1,414 @@
+/**
+  ******************************************************************************
+  * @file      startup_stm32f302x8.s
+  * @author    MCD Application Team
+  * @brief     STM32F302x6/STM32F302x8 devices vector table for GCC toolchain.
+  *            This module performs:
+  *                - Set the initial SP
+  *                - Set the initial PC == Reset_Handler,
+  *                - Set the vector table entries with the exceptions ISR address,
+  *                - Configure the clock system  
+  *                - Branches to main in the C library (which eventually
+  *                  calls main()).
+  *            After Reset the Cortex-M4 processor is in Thread mode,
+  *            priority is Privileged, and the Stack is set to Main.
+  ******************************************************************************
+  * @attention
+  *
+  * <h2><center>&copy; Copyright (c) 2016 STMicroelectronics.
+  * All rights reserved.</center></h2>
+  *
+  * This software component is licensed by ST under BSD 3-Clause license,
+  * the "License"; You may not use this file except in compliance with the
+  * License. You may obtain a copy of the License at:
+  *                        opensource.org/licenses/BSD-3-Clause
+  *
+  ******************************************************************************
+  */
+
+  .syntax unified
+	.cpu cortex-m4
+	.fpu softvfp
+	.thumb
+
+.global	g_pfnVectors
+.global	Default_Handler
+
+/* start address for the initialization values of the .data section.
+defined in linker script */
+.word	_sidata
+/* start address for the .data section. defined in linker script */
+.word	_sdata
+/* end address for the .data section. defined in linker script */
+.word	_edata
+/* start address for the .bss section. defined in linker script */
+.word	_sbss
+/* end address for the .bss section. defined in linker script */
+.word	_ebss
+
+.equ  BootRAM,        0xF1E0F85F
+/**
+ * @brief  This is the code that gets called when the processor first
+ *          starts execution following a reset event. Only the absolutely
+ *          necessary set is performed, after which the application
+ *          supplied main() routine is called.
+ * @param  None
+ * @retval : None
+*/
+
+    .section	.text.Reset_Handler
+	.weak	Reset_Handler
+	.type	Reset_Handler, %function
+Reset_Handler:
+  ldr   sp, =_estack    /* Atollic update: set stack pointer */
+
+/* Copy the data segment initializers from flash to SRAM */
+  movs	r1, #0
+  b	LoopCopyDataInit
+
+CopyDataInit:
+	ldr	r3, =_sidata
+	ldr	r3, [r3, r1]
+	str	r3, [r0, r1]
+	adds	r1, r1, #4
+
+LoopCopyDataInit:
+	ldr	r0, =_sdata
+	ldr	r3, =_edata
+	adds	r2, r0, r1
+	cmp	r2, r3
+	bcc	CopyDataInit
+	ldr	r2, =_sbss
+	b	LoopFillZerobss
+/* Zero fill the bss segment. */
+FillZerobss:
+	movs	r3, #0
+	str	r3, [r2], #4
+
+LoopFillZerobss:
+	ldr	r3, = _ebss
+	cmp	r2, r3
+	bcc	FillZerobss
+
+/* Call the clock system intitialization function.*/
+    bl  SystemInit
+/* Call static constructors */
+    bl __libc_init_array
+/* Call the application's entry point.*/
+	bl	main
+
+LoopForever:
+    b LoopForever
+    
+.size	Reset_Handler, .-Reset_Handler
+
+/**
+ * @brief  This is the code that gets called when the processor receives an
+ *         unexpected interrupt.  This simply enters an infinite loop, preserving
+ *         the system state for examination by a debugger.
+ *
+ * @param  None
+ * @retval : None
+*/
+    .section	.text.Default_Handler,"ax",%progbits
+Default_Handler:
+Infinite_Loop:
+	b	Infinite_Loop
+	.size	Default_Handler, .-Default_Handler
+/******************************************************************************
+*
+* The minimal vector table for a Cortex-M4.  Note that the proper constructs
+* must be placed on this to ensure that it ends up at physical address
+* 0x0000.0000.
+*
+******************************************************************************/
+ 	.section	.isr_vector,"a",%progbits
+	.type	g_pfnVectors, %object
+	.size	g_pfnVectors, .-g_pfnVectors
+
+
+g_pfnVectors:
+	.word	_estack
+	.word	Reset_Handler
+	.word	NMI_Handler
+	.word	HardFault_Handler
+	.word	MemManage_Handler
+	.word	BusFault_Handler
+	.word	UsageFault_Handler
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	SVC_Handler
+	.word	DebugMon_Handler
+	.word	0
+	.word	PendSV_Handler
+	.word	SysTick_Handler
+	.word	WWDG_IRQHandler
+	.word	PVD_IRQHandler
+	.word	TAMP_STAMP_IRQHandler
+	.word	RTC_WKUP_IRQHandler
+	.word	FLASH_IRQHandler
+	.word	RCC_IRQHandler
+	.word	EXTI0_IRQHandler
+	.word	EXTI1_IRQHandler
+	.word	EXTI2_TSC_IRQHandler
+	.word	EXTI3_IRQHandler
+	.word	EXTI4_IRQHandler
+	.word	DMA1_Channel1_IRQHandler
+	.word	DMA1_Channel2_IRQHandler
+	.word	DMA1_Channel3_IRQHandler
+	.word	DMA1_Channel4_IRQHandler
+	.word	DMA1_Channel5_IRQHandler
+	.word	DMA1_Channel6_IRQHandler
+	.word	DMA1_Channel7_IRQHandler
+	.word	ADC1_IRQHandler
+	.word	USB_HP_CAN_TX_IRQHandler
+	.word	USB_LP_CAN_RX0_IRQHandler
+	.word	CAN_RX1_IRQHandler
+	.word	CAN_SCE_IRQHandler
+	.word	EXTI9_5_IRQHandler
+	.word	TIM1_BRK_TIM15_IRQHandler
+	.word	TIM1_UP_TIM16_IRQHandler
+	.word	TIM1_TRG_COM_TIM17_IRQHandler
+	.word	TIM1_CC_IRQHandler
+	.word	TIM2_IRQHandler
+	.word	0
+	.word	0
+	.word	I2C1_EV_IRQHandler
+	.word	I2C1_ER_IRQHandler
+	.word	I2C2_EV_IRQHandler
+	.word	I2C2_ER_IRQHandler
+	.word	0
+	.word	SPI2_IRQHandler
+	.word	USART1_IRQHandler
+	.word	USART2_IRQHandler
+	.word	USART3_IRQHandler
+	.word	EXTI15_10_IRQHandler
+	.word	RTC_Alarm_IRQHandler
+	.word	USBWakeUp_IRQHandler
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	SPI3_IRQHandler
+	.word	0
+	.word	0
+	.word	TIM6_DAC_IRQHandler
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	COMP2_IRQHandler
+	.word	COMP4_6_IRQHandler
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	I2C3_EV_IRQHandler
+	.word	I2C3_ER_IRQHandler
+	.word	USB_HP_IRQHandler
+	.word	USB_LP_IRQHandler
+	.word	USBWakeUp_RMP_IRQHandler
+	.word	0
+	.word	0
+	.word	0
+	.word	0
+	.word	FPU_IRQHandler
+
+/*******************************************************************************
+*
+* Provide weak aliases for each Exception handler to the Default_Handler.
+* As they are weak aliases, any function with the same name will override
+* this definition.
+*
+*******************************************************************************/
+
+  .weak	NMI_Handler
+	.thumb_set NMI_Handler,Default_Handler
+
+  .weak	HardFault_Handler
+	.thumb_set HardFault_Handler,Default_Handler
+
+  .weak	MemManage_Handler
+	.thumb_set MemManage_Handler,Default_Handler
+
+  .weak	BusFault_Handler
+	.thumb_set BusFault_Handler,Default_Handler
+
+	.weak	UsageFault_Handler
+	.thumb_set UsageFault_Handler,Default_Handler
+
+	.weak	SVC_Handler
+	.thumb_set SVC_Handler,Default_Handler
+
+	.weak	DebugMon_Handler
+	.thumb_set DebugMon_Handler,Default_Handler
+
+	.weak	PendSV_Handler
+	.thumb_set PendSV_Handler,Default_Handler
+
+	.weak	SysTick_Handler
+	.thumb_set SysTick_Handler,Default_Handler
+
+	.weak	WWDG_IRQHandler
+	.thumb_set WWDG_IRQHandler,Default_Handler
+
+	.weak	PVD_IRQHandler
+	.thumb_set PVD_IRQHandler,Default_Handler
+
+	.weak	TAMP_STAMP_IRQHandler
+	.thumb_set TAMP_STAMP_IRQHandler,Default_Handler
+
+	.weak	RTC_WKUP_IRQHandler
+	.thumb_set RTC_WKUP_IRQHandler,Default_Handler
+
+	.weak	FLASH_IRQHandler
+	.thumb_set FLASH_IRQHandler,Default_Handler
+
+	.weak	RCC_IRQHandler
+	.thumb_set RCC_IRQHandler,Default_Handler
+
+	.weak	EXTI0_IRQHandler
+	.thumb_set EXTI0_IRQHandler,Default_Handler
+
+	.weak	EXTI1_IRQHandler
+	.thumb_set EXTI1_IRQHandler,Default_Handler
+
+	.weak	EXTI2_TSC_IRQHandler
+	.thumb_set EXTI2_TSC_IRQHandler,Default_Handler
+
+	.weak	EXTI3_IRQHandler
+	.thumb_set EXTI3_IRQHandler,Default_Handler
+
+	.weak	EXTI4_IRQHandler
+	.thumb_set EXTI4_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel1_IRQHandler
+	.thumb_set DMA1_Channel1_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel2_IRQHandler
+	.thumb_set DMA1_Channel2_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel3_IRQHandler
+	.thumb_set DMA1_Channel3_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel4_IRQHandler
+	.thumb_set DMA1_Channel4_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel5_IRQHandler
+	.thumb_set DMA1_Channel5_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel6_IRQHandler
+	.thumb_set DMA1_Channel6_IRQHandler,Default_Handler
+
+	.weak	DMA1_Channel7_IRQHandler
+	.thumb_set DMA1_Channel7_IRQHandler,Default_Handler
+
+	.weak	ADC1_IRQHandler
+	.thumb_set ADC1_IRQHandler,Default_Handler
+
+	.weak	USB_HP_CAN_TX_IRQHandler
+	.thumb_set USB_HP_CAN_TX_IRQHandler,Default_Handler
+
+	.weak	USB_LP_CAN_RX0_IRQHandler
+	.thumb_set USB_LP_CAN_RX0_IRQHandler,Default_Handler
+
+	.weak	CAN_RX1_IRQHandler
+	.thumb_set CAN_RX1_IRQHandler,Default_Handler
+
+	.weak	CAN_SCE_IRQHandler
+	.thumb_set CAN_SCE_IRQHandler,Default_Handler
+
+	.weak	EXTI9_5_IRQHandler
+	.thumb_set EXTI9_5_IRQHandler,Default_Handler
+
+	.weak	TIM1_BRK_TIM15_IRQHandler
+	.thumb_set TIM1_BRK_TIM15_IRQHandler,Default_Handler
+
+	.weak	TIM1_UP_TIM16_IRQHandler
+	.thumb_set TIM1_UP_TIM16_IRQHandler,Default_Handler
+
+	.weak	TIM1_TRG_COM_TIM17_IRQHandler
+	.thumb_set TIM1_TRG_COM_TIM17_IRQHandler,Default_Handler
+
+	.weak	TIM1_CC_IRQHandler
+	.thumb_set TIM1_CC_IRQHandler,Default_Handler
+
+	.weak	TIM2_IRQHandler
+	.thumb_set TIM2_IRQHandler,Default_Handler
+
+	.weak	I2C1_EV_IRQHandler
+	.thumb_set I2C1_EV_IRQHandler,Default_Handler
+
+	.weak	I2C1_ER_IRQHandler
+	.thumb_set I2C1_ER_IRQHandler,Default_Handler
+
+	.weak	I2C2_EV_IRQHandler
+	.thumb_set I2C2_EV_IRQHandler,Default_Handler
+
+	.weak	I2C2_ER_IRQHandler
+	.thumb_set I2C2_ER_IRQHandler,Default_Handler
+
+	.weak	SPI2_IRQHandler
+	.thumb_set SPI2_IRQHandler,Default_Handler
+
+	.weak	USART1_IRQHandler
+	.thumb_set USART1_IRQHandler,Default_Handler
+
+	.weak	USART2_IRQHandler
+	.thumb_set USART2_IRQHandler,Default_Handler
+
+	.weak	USART3_IRQHandler
+	.thumb_set USART3_IRQHandler,Default_Handler
+
+	.weak	EXTI15_10_IRQHandler
+	.thumb_set EXTI15_10_IRQHandler,Default_Handler
+
+	.weak	RTC_Alarm_IRQHandler
+	.thumb_set RTC_Alarm_IRQHandler,Default_Handler
+
+	.weak	USBWakeUp_IRQHandler
+	.thumb_set USBWakeUp_IRQHandler,Default_Handler
+
+	.weak	SPI3_IRQHandler
+	.thumb_set SPI3_IRQHandler,Default_Handler
+
+	.weak	TIM6_DAC_IRQHandler
+	.thumb_set TIM6_DAC_IRQHandler,Default_Handler
+	
+	.weak	COMP2_IRQHandler
+	.thumb_set COMP2_IRQHandler,Default_Handler
+	
+	.weak	COMP4_6_IRQHandler
+	.thumb_set COMP4_6_IRQHandler,Default_Handler
+  
+	.weak	I2C3_EV_IRQHandler
+	.thumb_set I2C3_EV_IRQHandler,Default_Handler  
+	
+	.weak	I2C3_ER_IRQHandler
+	.thumb_set I2C3_ER_IRQHandler,Default_Handler	
+	
+	.weak	USB_HP_IRQHandler
+	.thumb_set USB_HP_IRQHandler,Default_Handler
+	
+	.weak	USB_LP_IRQHandler
+	.thumb_set USB_LP_IRQHandler,Default_Handler
+	
+	.weak	USBWakeUp_RMP_IRQHandler
+	.thumb_set USBWakeUp_RMP_IRQHandler,Default_Handler
+	
+	.weak	FPU_IRQHandler
+	.thumb_set FPU_IRQHandler,Default_Handler
+/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
diff --git a/stm32f302r8tx.ld b/stm32f302r8tx.ld
new file mode 100644
index 0000000..f8275ec
--- /dev/null
+++ b/stm32f302r8tx.ld
@@ -0,0 +1,201 @@
+/*
+******************************************************************************
+**
+
+**  File        : LinkerScript.ld
+**
+**  Author		: Auto-generated by Ac6 System Workbench
+**
+**  Abstract    : Linker script for STM32F302R8Tx series
+**                64Kbytes FLASH and 16Kbytes RAM
+**
+**                Set heap size, stack size and stack location according
+**                to application requirements.
+**
+**                Set memory bank area and size if external memory is used.
+**
+**  Target      : STMicroelectronics STM32
+**
+**  Distribution: The file is distributed “as is,” without any warranty
+**                of any kind.
+**
+*****************************************************************************
+** @attention
+**
+** <h2><center>&copy; COPYRIGHT(c) 2014 Ac6</center></h2>
+**
+** Redistribution and use in source and binary forms, with or without modification,
+** are permitted provided that the following conditions are met:
+**   1. Redistributions of source code must retain the above copyright notice,
+**      this list of conditions and the following disclaimer.
+**   2. Redistributions in binary form must reproduce the above copyright notice,
+**      this list of conditions and the following disclaimer in the documentation
+**      and/or other materials provided with the distribution.
+**   3. Neither the name of Ac6 nor the names of its contributors
+**      may be used to endorse or promote products derived from this software
+**      without specific prior written permission.
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+** AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+** DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+** SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+** OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+**
+*****************************************************************************
+*/
+
+/* Entry Point */
+ENTRY(Reset_Handler)
+
+/* Highest address of the user mode stack */
+_estack = 0x20004000;    /* end of RAM */
+/* Generate a link error if heap and stack don't fit into RAM */
+_Min_Heap_Size = 0x200;      /* required amount of heap  */
+_Min_Stack_Size = 0x400; /* required amount of stack */
+
+_Flash_Base = 0x08000000;
+_Flash_Size = 64K;
+_Bootloader_Size = 0x2000; /* Reserver 8k for bootloader */
+
+/* Specify the memory areas */
+MEMORY
+{
+FLASH (rx)      : ORIGIN = _Flash_Base, LENGTH = _Bootloader_Size
+USER_FLASH (xrw): ORIGIN = _Flash_Base + _Bootloader_Size, LENGTH = _Flash_Size - _Bootloader_Size
+RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 16K
+}
+
+/* Define output sections */
+SECTIONS
+{
+  /* The startup code goes first into FLASH */
+  .isr_vector :
+  {
+    . = ALIGN(4);
+    KEEP(*(.isr_vector)) /* Startup code */
+    . = ALIGN(4);
+  } >FLASH
+
+  /* The program code and other data goes into FLASH */
+  .text :
+  {
+    . = ALIGN(4);
+    *(.text)           /* .text sections (code) */
+    *(.text*)          /* .text* sections (code) */
+    *(.glue_7)         /* glue arm to thumb code */
+    *(.glue_7t)        /* glue thumb to arm code */
+    *(.eh_frame)
+
+    KEEP (*(.init))
+    KEEP (*(.fini))
+
+    . = ALIGN(4);
+    _etext = .;        /* define a global symbols at end of code */
+  } >FLASH
+
+  /* Constant data goes into FLASH */
+  .rodata :
+  {
+    . = ALIGN(4);
+    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
+    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+    . = ALIGN(4);
+  } >FLASH
+
+  .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
+  .ARM : {
+    __exidx_start = .;
+    *(.ARM.exidx*)
+    __exidx_end = .;
+  } >FLASH
+
+  .preinit_array     :
+  {
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP (*(.preinit_array*))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+  } >FLASH
+  .init_array :
+  {
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP (*(SORT(.init_array.*)))
+    KEEP (*(.init_array*))
+    PROVIDE_HIDDEN (__init_array_end = .);
+  } >FLASH
+  .fini_array :
+  {
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP (*(SORT(.fini_array.*)))
+    KEEP (*(.fini_array*))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+  } >FLASH
+
+  /* used by the startup to initialize data */
+  _sidata = LOADADDR(.data);
+
+  /* Initialized data sections goes into RAM, load LMA copy after code */
+  .data : 
+  {
+    . = ALIGN(4);
+    _sdata = .;        /* create a global symbol at data start */
+    *(.data)           /* .data sections */
+    *(.data*)          /* .data* sections */
+
+    . = ALIGN(4);
+    _edata = .;        /* define a global symbol at data end */
+  } >RAM AT> FLASH
+
+  _user_flash_start = ORIGIN(USER_FLASH);
+  _user_flash_size = LENGTH(USER_FLASH);
+  .user_flash : {
+    . = ALIGN(4);
+    *(.user_flash)
+  } >USER_FLASH
+
+  
+  /* Uninitialized data section */
+  . = ALIGN(4);
+  .bss :
+  {
+    /* This is used by the startup in order to initialize the .bss secion */
+    _sbss = .;         /* define a global symbol at bss start */
+    __bss_start__ = _sbss;
+    *(.bss)
+    *(.bss*)
+    *(COMMON)
+
+    . = ALIGN(4);
+    _ebss = .;         /* define a global symbol at bss end */
+    __bss_end__ = _ebss;
+  } >RAM
+
+  /* User_heap_stack section, used to check that there is enough RAM left */
+  ._user_heap_stack :
+  {
+    . = ALIGN(8);
+    PROVIDE ( end = . );
+    PROVIDE ( _end = . );
+    . = . + _Min_Heap_Size;
+    . = . + _Min_Stack_Size;
+    . = ALIGN(8);
+  } >RAM
+
+  
+
+  /* Remove information from the standard libraries */
+  /DISCARD/ :
+  {
+    libc.a ( * )
+    libm.a ( * )
+    libgcc.a ( * )
+  }
+
+  .ARM.attributes 0 : { *(.ARM.attributes) }
+}
+
+
diff --git a/tools/__pycache__/dsss_demod_test_waveform_gen.cpython-38.pyc b/tools/__pycache__/dsss_demod_test_waveform_gen.cpython-38.pyc
new file mode 100644
index 0000000..1512990
--- /dev/null
+++ b/tools/__pycache__/dsss_demod_test_waveform_gen.cpython-38.pyc
diff --git a/tools/__pycache__/presig_gen.cpython-38.pyc b/tools/__pycache__/presig_gen.cpython-38.pyc
new file mode 100644
index 0000000..b28b1a9
--- /dev/null
+++ b/tools/__pycache__/presig_gen.cpython-38.pyc
diff --git a/tools/butter_filter_gen.py b/tools/butter_filter_gen.py
new file mode 100644
index 0000000..0bb81bc
--- /dev/null
+++ b/tools/butter_filter_gen.py
@@ -0,0 +1,93 @@
+#!/usr/bin/env python3
+
+import math
+import sys
+import contextlib
+
+import scipy.signal as sig
+import numpy as np
+
+
+@contextlib.contextmanager
+def wrap(left='{', right='}', file=None, end=''):
+    print(left, file=file, end=end)
+    yield
+    print(right, file=file, end=end)
+
+@contextlib.contextmanager
+def print_include_guards(macro_name):
+    print(f'#ifndef {macro_name}')
+    print(f'#define {macro_name}')
+    print()
+    yield
+    print()
+    print(f'#endif /* {macro_name} */')
+
+macro_float = lambda f: f'{f}'.replace('.', 'F').replace('-', 'N').replace('+', 'P')
+
+ordinal = lambda n: "%d%s" % (n,"tsnrhtdd"[(n//10%10!=1)*(n%10<4)*n%10::4])
+
+SI_TABLE = {-18: 'a', -15: 'f', -12: 'p', -9: 'n', -6: 'µ', -3: 'm', 0: '', 3: 'k', 6: 'M', 9: 'G', 12: 'T', 15: 'P', 18: 'E'}
+def siprefix(x, space=' ', unit=''):
+    l = math.log10(x)//3*3
+    if l in SI_TABLE:
+        return f'{x/10**l}{space}{SI_TABLE[l]}{unit}'
+    return f'{x}{space}{unit}'
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-m', '--macro-name', default='butter_filter', help='Prefix for output macro names')
+    parser.add_argument('fc', type=float, help='Corner frequency [Hz]')
+    parser.add_argument('fs', type=float, help='Sampling rate [Hz]')
+    parser.add_argument('n', type=int, nargs='?', default=6, help='Filter order')
+    args = parser.parse_args()
+    
+    sos = sig.butter(args.n, args.fc, fs=args.fs, output='sos')
+
+    print('/* THIS IS A GENERATED FILE. DO NOT EDIT! */')
+    print()
+    with print_include_guards(f'__BUTTER_FILTER_GENERATED_{args.n}_{macro_float(args.fc)}_{macro_float(args.fs)}__'):
+
+        print(f'/* {ordinal(args.n)} order Butterworth IIR filter coefficients')
+        print(f' *')
+        print(f' * corner frequency f_c = {siprefix(args.fc)}Hz')
+        print(f' * sampling rate f_s = {siprefix(args.fs)}Hz')
+        print(f' */')
+        print()
+        print(f'#define {args.macro_name.upper()}_ORDER {args.n}')
+        print(f'#define {args.macro_name.upper()}_CLEN {(args.n+1)//2}')
+
+        # scipy.signal.butter by default returns extremely small bs for the first biquad and large ones for subsequent
+        # sections. Balance magnitudes to reduce possible rounding errors.
+        first_biquad_bs = sos[0][:3]
+        approx_mag = round(math.log10(np.mean(first_biquad_bs)))
+        mags = [approx_mag // len(sos)] * len(sos)
+        mags[0] += approx_mag - sum(mags)
+        sos[0][:3] /= 10**approx_mag
+        sos = np.array([ sec * np.array([10**mag, 10**mag, 10**mag, 1, 1, 1]) for mag, sec in zip(mags, sos) ])
+
+        ones = np.ones([100000])
+        _, steady_state = sig.sosfilt(sos, ones, zi=np.zeros([(args.n+1)//2, 2]))
+
+        print(f'#define {args.macro_name.upper()}_COEFF ', end='')
+        for sec in sos:
+            bs, ases = sec[:3], sec[4:6]
+
+            with wrap():
+                print('.b=', end='')
+                with wrap():
+                    print(', '.join(f'{v}' for v in bs), end='')
+                print(', .a=', end='')
+                with wrap():
+                    print(', '.join(f'{v}' for v in ases), end='')
+            print(', ', end='')
+        print()
+
+        print(f'#define {args.macro_name.upper()}_STEADY_STATE ', end='')
+        for sec in steady_state:
+            with wrap():
+                print(', '.join(f'{v}' for v in sec), end='')
+            print(', ', end='')
+        print()
+
diff --git a/tools/crypto_test.c b/tools/crypto_test.c
new file mode 100644
index 0000000..410fac2
--- /dev/null
+++ b/tools/crypto_test.c
@@ -0,0 +1,46 @@
+
+#include <stdint.h>
+#include <math.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/fcntl.h>
+
+#include "crypto.h"
+
+void oob_trigger_activated(enum trigger_domain domain, int serial) {
+    printf("oob_trigger_activated(%d, %d)\n", domain, serial);
+    fflush(stdout);
+}
+
+void print_usage() {
+    fprintf(stderr, "Usage: crypto_test [auth_key_hex]\n");
+}
+
+int main(int argc, char **argv) {
+    if (argc != 2) {
+        fprintf(stderr, "Error: Invalid arguments.\n");
+        print_usage();
+        return 1;
+    }
+
+    uint8_t auth_key[16];
+
+    for (size_t i=0; argv[1][i+0] != '\0' && argv[1][i+1] != '\0' && i/2<sizeof(auth_key); i+= 2) {
+        char buf[3] = { argv[1][i+0], argv[1][i+1], 0};
+        char *endptr;
+        auth_key[i/2] = strtoul(buf, &endptr, 16);
+        if (!endptr || *endptr != '\0') {
+            fprintf(stderr, "Invalid authkey\n");
+            return 1;
+        }
+    }
+
+    printf("rc=%d\n", oob_message_received(auth_key));
+
+    return 0;
+}
diff --git a/tools/crypto_test_runner.py b/tools/crypto_test_runner.py
new file mode 100644
index 0000000..34c8b59
--- /dev/null
+++ b/tools/crypto_test_runner.py
@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+import subprocess
+from os import path
+import binascii
+import re
+
+import presig_gen
+
+def do_test(domain, value, height, root_key, binary, expect_fail=False):
+    auth = presig_gen.gen_at_height(domain, value, height, root_key)
+    auth = binascii.hexlify(auth).decode()
+
+    output = subprocess.check_output([binary, auth])
+    *lines, rc_line = output.decode().splitlines()
+    rc = int(re.match('^rc=(\d+)$', rc_line).group(1))
+    assert expect_fail == (rc == 0)
+
+def run_tests(root_key, max_height, binary):
+    for domain, value in {
+            'all': 'all',
+            'vendor': presig_gen.TEST_VENDOR,
+            'series': presig_gen.TEST_SERIES,
+            'country': presig_gen.TEST_COUNTRY,
+            'region': presig_gen.TEST_REGION,
+            }.items():
+        for height in range(max_height):
+            do_test(domain, value, height, root_key, binary)
+            do_test(domain, 'fail', height, root_key, binary, expect_fail=True)
+            do_test('fail', 'fail', height, root_key, binary, expect_fail=True)
+            do_test('', '', height, root_key, binary, expect_fail=True)
+        do_test(domain, value, max_height, root_key, binary, expect_fail=True)
+        do_test(domain, value, max_height+1, root_key, binary, expect_fail=True)
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('keyfile', help='Root key file')
+    parser.add_argument('max_height', type=int, default=8, nargs='?', help='Height of generated prekeys')
+    default_binary = path.abspath(path.join(path.dirname(__file__), '../build/tools/crypto_test'))
+    parser.add_argument('binary', default=default_binary, nargs='?', help='crypto_test binary to use')
+    args = parser.parse_args()
+
+    with open(args.keyfile, 'r') as f:
+        root_key = binascii.unhexlify(f.read().strip())
+
+    run_tests(root_key, args.max_height, args.binary)
diff --git a/tools/cwt_wavelet_header_gen.py b/tools/cwt_wavelet_header_gen.py
new file mode 100644
index 0000000..8be785b
--- /dev/null
+++ b/tools/cwt_wavelet_header_gen.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+
+import textwrap
+
+import scipy.signal as sig
+import numpy as np
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('n', type=int, help='Window size')
+    parser.add_argument('w', type=float, help='Wavelet width')
+    parser.add_argument('-v', '--variable', default='cwt_ricker_table', help='Name for alias variable pointing to generated wavelet LUT')
+    args = parser.parse_args()
+    
+    print(f'/* CWT Ricker wavelet LUT for {args.n} sample window of width {args.w}. */')
+    varname = f'cwt_ricker_{args.n}_window_{str(args.w).replace(".", "F")}'
+    print(f'const float {varname}[{args.n}] = {{')
+
+    win = sig.ricker(args.n, args.w)
+    par = ' '.join(f'{f:>015.12e}f,' for f in win)
+    print(textwrap.fill(par,
+        initial_indent=' '*4, subsequent_indent=' '*4,
+        width=120,
+        replace_whitespace=False, drop_whitespace=False))
+    print('};')
+    print()
+    print(f'const float * const {args.variable} __attribute__((weak)) = {varname};')
+
diff --git a/tools/dsss_demod_test.c b/tools/dsss_demod_test.c
new file mode 100644
index 0000000..f7df111
--- /dev/null
+++ b/tools/dsss_demod_test.c
@@ -0,0 +1,109 @@
+
+#include <stdint.h>
+#include <math.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/fcntl.h>
+
+#include "dsss_demod.h"
+
+void handle_dsss_received(symbol_t data[static TRANSMISSION_SYMBOLS]) {
+    printf("data sequence received: [ ");
+    for (size_t i=0; i<TRANSMISSION_SYMBOLS; i++) {
+        //printf("%+3d", ((data[i]&1) ? 1 : -1) * (data[i]>>1));
+        printf("%2d", data[i]);
+        if (i+1 < TRANSMISSION_SYMBOLS)
+            printf(", ");
+    }
+    printf(" ]\n");
+}
+
+void print_usage() {
+    fprintf(stderr, "Usage: dsss_demod_test [test_data.bin] [optional recording channel number]\n");
+}
+
+int main(int argc, char **argv) {
+    if (argc != 2 && argc != 3) {
+        fprintf(stderr, "Error: Invalid arguments.\n");
+        print_usage();
+        return 1;
+    }
+
+    int fd = open(argv[1], O_RDONLY);
+    struct stat st;
+    if (fstat(fd, &st)) {
+        fprintf(stderr, "Error querying test data file size: %s\n", strerror(errno));
+        return 2;
+    }
+
+    if (st.st_size < 0 || st.st_size > 10000000) {
+        fprintf(stderr, "Error reading test data: too much test data (size=%zd)\n", st.st_size);
+        return 2;
+    }
+
+    if (st.st_size % sizeof(float) != 0) {
+        fprintf(stderr, "Error reading test data: file size is not divisible by %zd (size=%zd)\n", sizeof(float), st.st_size);
+        return 2;
+    }
+
+    char *buf = malloc(st.st_size);
+    if (!buf) {
+        fprintf(stderr, "Error allocating memory");
+        return 2;
+    }
+
+    int record_channel = -1;
+    if (argc == 3) {
+        char *endptr;
+        record_channel = strtoul(argv[2], &endptr, 10);
+        if (!endptr || *endptr != '\0') {
+            fprintf(stderr, "Invalid channel number \"%s\"\n", argv[2]);
+            return 1;
+        }
+    }
+
+    if (record_channel != -1)
+        fprintf(stderr, "Reading %zd samples test data...", st.st_size/sizeof(float));
+    ssize_t nread = 0;
+    while (nread < st.st_size) {
+        ssize_t rc = read(fd, buf + nread, st.st_size - nread);
+
+        if (rc == -EINTR || rc == -EAGAIN)
+            continue;
+
+        if (rc < 0) {
+            fprintf(stderr, "\nError reading test data: %s\n", strerror(errno));
+            return 2;
+        }
+        
+        if (rc == 0) {
+            fprintf(stderr, "\nError reading test data: Unexpected end of file\n");
+            return 2;
+        }
+
+        nread += rc;
+    }
+    if (record_channel != -1)
+        fprintf(stderr, " done.\n");
+
+    const size_t n_samples = st.st_size / sizeof(float);
+    float *buf_f = (float *)buf;
+
+    if (record_channel != -1)
+        fprintf(stderr, "Starting simulation.\n");
+
+    struct dsss_demod_state demod;
+    dsss_demod_init(&demod);
+    for (size_t i=0; i<n_samples; i++) {
+        //fprintf(stderr, "Iteration %zd/%zd\n", i, n_samples);
+        dsss_demod_step(&demod, buf_f[i], i);
+    }
+
+    free(buf);
+    return 0;
+}
diff --git a/tools/dsss_demod_test_runner.py b/tools/dsss_demod_test_runner.py
new file mode 100644
index 0000000..d3c3cfc
--- /dev/null
+++ b/tools/dsss_demod_test_runner.py
@@ -0,0 +1,241 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+from os import path
+import subprocess
+import json
+from collections import namedtuple, defaultdict
+from tqdm import tqdm
+import uuid
+import multiprocessing
+import sqlite3 
+import time
+from urllib.parse import urlparse
+import tempfile
+import itertools
+
+import numpy as np
+np.set_printoptions(linewidth=240)
+
+from dsss_demod_test_waveform_gen import load_noise_gen, modulate as dsss_modulate
+
+
+def build_test_binary(nbits, thf, decimation, symbols, cachedir):
+    build_id = str(uuid.uuid4())
+    builddir = path.join(cachedir, build_id)
+    os.mkdir(builddir)
+
+    cwd = path.join(path.dirname(__file__), '..')
+
+    env = os.environ.copy()
+    env['BUILDDIR'] = path.abspath(builddir)
+    env['DSSS_GOLD_CODE_NBITS'] = str(nbits)
+    env['DSSS_DECIMATION'] = str(decimation)
+    env['DSSS_THRESHOLD_FACTOR'] = str(thf)
+    env['DSSS_WAVELET_WIDTH'] = str(0.73 * decimation)
+    env['DSSS_WAVELET_LUT_SIZE'] = str(10 * decimation)
+    env['TRANSMISSION_SYMBOLS'] = str(symbols)
+
+    with open(path.join(builddir, 'make_stdout.txt'), 'w') as stdout,\
+         open(path.join(builddir, 'make_stderr.txt'), 'w') as stderr:
+        subprocess.run(['make', 'clean', os.path.abspath(path.join(builddir, 'tools/dsss_demod_test'))],
+                env=env, cwd=cwd, check=True, stdout=stdout, stderr=stderr)
+
+    return build_id
+
+def sequence_matcher(test_data, decoded, max_shift=3):
+    match_result = []
+    for shift in range(-max_shift, max_shift):
+        failures = -shift if shift < 0 else 0 # we're skipping the first $shift symbols
+        a = test_data if shift > 0 else test_data[-shift:]
+        b = decoded if shift < 0 else decoded[shift:]
+        for i, (ref, found) in enumerate(itertools.zip_longest(a, b)):
+            if ref is None: # end of signal
+                break
+            if ref != found:
+                failures += 1
+        match_result.append(failures)
+    failures = min(match_result)
+    return failures/len(test_data)
+
+ResultParams = namedtuple('ResultParams', ['nbits', 'thf', 'decimation', 'symbols', 'seed', 'amplitude', 'background'])
+
+def run_test(seed, amplitude_spec, background, nbits, decimation, symbols, thfs, lookup_binary, cachedir):
+    noise_gen, noise_params = load_noise_gen(background)
+
+    test_data = np.random.RandomState(seed=seed).randint(0, 2 * (2**nbits), symbols)
+    
+    signal = np.repeat(dsss_modulate(test_data, nbits) * 2.0 - 1, decimation)
+    # We're re-using the seed here. This is not a problem.
+    noise = noise_gen(seed, len(signal), *noise_params)
+    amplitudes = amplitude_spec[0] * 10 ** np.linspace(0, amplitude_spec[1], amplitude_spec[2])
+    # DEBUG
+    my_pid = multiprocessing.current_process().pid
+    wql = len(amplitudes) * len(thfs)
+    print(f'[{my_pid}] starting, got workqueue of length {wql}')
+    i = 0
+    # Map lsb to sign to match test program
+    # test_data = (test_data>>1) * (2*(test_data&1) - 1)
+    # END DEBUG
+
+    output = []
+    for amp in amplitudes:
+        with tempfile.NamedTemporaryFile(dir=cachedir) as f:
+            waveform = signal*amp + noise
+            f.write(waveform.astype('float32').tobytes())
+            f.flush()
+            # DEBUG
+            fcopy = f'/tmp/test-{path.basename(f.name)}'
+            import shutil
+            shutil.copy(f.name, fcopy)
+            # END DEBUG
+
+            for thf in thfs:
+                rpars = ResultParams(nbits, thf, decimation, symbols, seed, amp, background)
+                cmdline = [lookup_binary(nbits, thf, decimation, symbols), f.name]
+                # DEBUG
+                starttime = time.time()
+                # END DEBUG
+                try:
+                    proc = subprocess.run(cmdline, stdout=subprocess.PIPE, encoding='utf-8', check=True, timeout=300)
+
+                    lines = proc.stdout.splitlines()
+                    matched = [ l.partition('[')[2].partition(']')[0]
+                            for l in lines if l.strip().startswith('data sequence received:') ]
+                    matched = [ [ int(elem) for elem in l.split(',') ] for l in matched ]
+
+                    ser = min(sequence_matcher(test_data, match) for match in matched) if matched else None
+                    output.append((rpars, ser))
+                    # DEBUG
+                    #print(f'[{my_pid}] ran {i}/{wql}: time={time.time() - starttime}\n    {ser=}\n    {rpars}\n    {" ".join(cmdline)}\n    {fcopy}', flush=True)
+                    i += 1
+                    # END DEBUG
+
+                except subprocess.TimeoutExpired:
+                    output.append((rpars, None))
+                    # DEBUG
+                    print(f'[{my_pid}] ran {i}/{wql}: Timeout!\n    {rpars}\n    {" ".join(cmdline)}\n    {fcopy}', flush=True)
+                    i += 1
+                    # END DEBUG
+    print(f'[{my_pid}] finished.')
+    return output
+
+def parallel_generator(db, table, columns, builder, param_list, desc, context={}, params_mapper=lambda *args: args,
+        disable_cache=False):
+    with multiprocessing.Pool(multiprocessing.cpu_count()) as pool:
+        with db as conn:
+            jobs = []
+            for params in param_list:
+                found_res = conn.execute(
+                            f'SELECT result FROM {table} WHERE ({",".join(columns)}) = ({",".join("?"*len(columns))})',
+                        params_mapper(*params)).fetchone()
+
+                if found_res and not disable_cache:
+                    yield params, json.loads(*found_res)
+
+                else:
+                    jobs.append((params, pool.apply_async(builder, params, context)))
+
+        pool.close()
+        print('Using', len(param_list) - len(jobs), 'cached jobs', flush=True)
+        with tqdm(total=len(jobs), desc=desc) as tq:
+            for i, (params, res) in enumerate(jobs):
+                # DEBUG
+                print('Got result', i, params, res)
+                # END DEBUG
+                tq.update(1)
+                result = res.get()
+                with db as conn:
+                    conn.execute(f'INSERT INTO {table} VALUES ({"?,"*len(params)}?,?)',
+                            (*params_mapper(*params), json.dumps(result), timestamp()))
+                yield params, result
+        pool.join()
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-d', '--dump', help='Write results to JSON file')
+    parser.add_argument('-c', '--cachedir', default='dsss_test_cache', help='Directory to store build output and data in')
+    parser.add_argument('-n', '--no-cache', action='store_true', help='Disable result cache')
+    parser.add_argument('-b', '--batches', type=int, default=1, help='Number of batches to split the computation into')
+    parser.add_argument('-i', '--index', type=int, default=0, help='Batch index to compute')
+    parser.add_argument('-p', '--prepare', action='store_true', help='Prepare mode: compile runners, then exit.')
+    args = parser.parse_args()
+
+    DecoderParams = namedtuple('DecoderParams', ['nbits', 'thf', 'decimation', 'symbols'])
+#    dec_paramses = [ DecoderParams(nbits=nbits, thf=thf, decimation=decimation, symbols=20)
+#            for nbits in [5, 6]
+#            for thf in [4.5, 4.0, 5.0]
+#            for decimation in [10, 5, 22] ]
+    dec_paramses = [ DecoderParams(nbits=nbits, thf=thf, decimation=decimation, symbols=100)
+            for nbits in [5, 6]
+            for thf in [3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0]
+            for decimation in [1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 16, 22, 30, 40, 50] ]
+#    dec_paramses = [ DecoderParams(nbits=nbits, thf=thf, decimation=decimation, symbols=100)
+#            for nbits in [5, 6, 7, 8]
+#            for thf in [1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0]
+#            for decimation in [1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 16, 22, 30, 40, 50] ]
+
+    build_cache_dir = path.join(args.cachedir, 'builds')
+    data_cache_dir = path.join(args.cachedir, 'data')
+    os.makedirs(build_cache_dir, exist_ok=True)
+    os.makedirs(data_cache_dir, exist_ok=True)
+
+    build_db = sqlite3.connect(path.join(args.cachedir, 'build_db.sqlite3'))
+    build_db.execute('CREATE TABLE IF NOT EXISTS builds (nbits, thf, decimation, symbols, result, timestamp)')
+    timestamp = lambda: int(time.time()*1000)
+
+    builds = dict(parallel_generator(build_db, table='builds', columns=['nbits', 'thf', 'decimation', 'symbols'],
+            builder=build_test_binary, param_list=dec_paramses, desc='Building decoders',
+            context=dict(cachedir=build_cache_dir)))
+    print('Done building decoders.')
+    if args.prepare:
+        sys.exit(0)
+
+    GeneratorParams = namedtuple('GeneratorParams', ['seed', 'amplitude_spec', 'background'])
+    gen_params = [ GeneratorParams(rep, (5e-3, 1, 5), background)
+            #GeneratorParams(rep, (0.05e-3, 3.5, 50), background)
+            for rep in range(50)
+            for background in ['meas://fmeas_export_ocxo_2day.bin', 'synth://grid_freq_psd_spl_108pt.json'] ]
+#    gen_params = [ GeneratorParams(rep, (5e-3, 1, 5), background)
+#            for rep in range(1)
+#            for background in ['meas://fmeas_export_ocxo_2day.bin'] ]
+
+    data_db = sqlite3.connect(path.join(args.cachedir, 'data_db.sqlite3'))
+    data_db.execute('CREATE TABLE IF NOT EXISTS waveforms'
+                    '(seed, amplitude_spec, background, nbits, decimation, symbols, thresholds, result, timestamp)')
+
+    'SELECT FROM waveforms GROUP BY (amplitude_spec, background, nbits, decimation, symbols, thresholds, result)'
+
+    dec_param_groups = defaultdict(lambda: [])
+    for nbits, thf, decimation, symbols in dec_paramses:
+        dec_param_groups[(nbits, decimation, symbols)].append(thf)
+    waveform_params = [ (*gp, *dp, thfs) for gp in gen_params for dp, thfs in dec_param_groups.items() ]
+    print(f'Generated {len(waveform_params)} parameter sets')
+
+    # Separate out our batch
+    waveform_params = waveform_params[args.index::args.batches]
+
+    def lookup_binary(*params):
+        return path.join(build_cache_dir, builds[tuple(params)], 'tools/dsss_demod_test')
+
+    def params_mapper(seed, amplitude_spec, background, nbits, decimation, symbols, thresholds):
+        amplitude_spec = ','.join(str(x) for x in amplitude_spec)
+        thresholds = ','.join(str(x) for x in thresholds)
+        return seed, amplitude_spec, background, nbits, decimation, symbols, thresholds
+
+    results = []
+    for _params, chunk in parallel_generator(data_db, 'waveforms',
+            ['seed', 'amplitude_spec', 'background', 'nbits', 'decimation', 'symbols', 'thresholds'],
+            params_mapper=params_mapper,
+            builder=run_test,
+            param_list=waveform_params, desc='Simulating demodulation',
+            context=dict(cachedir=data_cache_dir, lookup_binary=lookup_binary),
+            disable_cache=args.no_cache):
+        results += chunk
+
+    if args.dump:
+        with open(args.dump, 'w') as f:
+            json.dump(results, f)
+
diff --git a/tools/dsss_demod_test_waveform_gen.py b/tools/dsss_demod_test_waveform_gen.py
new file mode 100644
index 0000000..414c553
--- /dev/null
+++ b/tools/dsss_demod_test_waveform_gen.py
@@ -0,0 +1,86 @@
+
+from os import path
+import json
+import functools
+
+import numpy as np
+import numbers
+import math
+from scipy import signal as sig
+import scipy.fftpack
+
+sampling_rate = 10 # sp/s
+
+# From https://github.com/mubeta06/python/blob/master/signal_processing/sp/gold.py
+preferred_pairs = {5:[[2],[1,2,3]], 6:[[5],[1,4,5]], 7:[[4],[4,5,6]],
+                        8:[[1,2,3,6,7],[1,2,7]], 9:[[5],[3,5,6]], 
+                        10:[[2,5,9],[3,4,6,8,9]], 11:[[9],[3,6,9]]}
+
+def gen_gold(seq1, seq2):
+    gold = [seq1, seq2]
+    for shift in range(len(seq1)):
+        gold.append(seq1 ^ np.roll(seq2, -shift))
+    return gold
+
+def gold(n):
+    n = int(n)
+    if not n in preferred_pairs:
+        raise KeyError('preferred pairs for %s bits unknown' % str(n))
+    t0, t1 = preferred_pairs[n]
+    (seq0, _st0), (seq1, _st1) = sig.max_len_seq(n, taps=t0), sig.max_len_seq(n, taps=t1)
+    return gen_gold(seq0, seq1)
+
+def modulate(data, nbits=5):
+    # 0, 1 -> -1, 1
+    mask = np.array(gold(nbits))*2 - 1
+    
+    sel = mask[data>>1]
+    data_lsb_centered = ((data&1)*2 - 1)
+
+    signal = (np.multiply(sel, np.tile(data_lsb_centered, (2**nbits-1, 1)).T).flatten() + 1) // 2
+    return np.hstack([ np.zeros(len(mask)), signal, np.zeros(len(mask)) ])
+
+def load_noise_meas_params(capture_file):
+    with open(capture_file, 'rb') as f:
+        meas_data = np.copy(np.frombuffer(f.read(), dtype='float32'))
+        meas_data -= np.mean(meas_data)
+        return (meas_data,)
+
+def mains_noise_measured(seed, n, meas_data):
+    last_valid = len(meas_data) - n
+    st = np.random.RandomState(seed)
+    start = st.randint(last_valid)
+    return meas_data[start:start+n] + 50.00
+
+def load_noise_synth_params(specfile):
+    with open(specfile) as f:
+        d = json.load(f)
+        return {'spl_x': np.linspace(*d['x_spec']),
+                'spl_N': d['x_spec'][2],
+                'psd_spl': (d['t'], d['c'], d['k']) }
+
+def mains_noise_synthetic(seed, n, psd_spl, spl_N, spl_x):
+    st = np.random.RandomState(seed)
+    noise = st.normal(size=spl_N) * 2
+    spec = scipy.fftpack.fft(noise) **2
+
+    spec *= np.exp(scipy.interpolate.splev(spl_x, psd_spl))
+
+    spec **= 1/2
+    
+    renoise = scipy.fftpack.ifft(spec)
+    return renoise[10000:][:n] + 50.00
+
+@functools.lru_cache()
+def load_noise_gen(url):
+    schema, refpath = url.split('://')
+    if not path.isabs(refpath):
+        refpath = path.abspath(path.join(path.dirname(__file__), refpath))
+
+    if schema == 'meas':
+        return mains_noise_measured, load_noise_meas_params(refpath)
+    elif schema == 'synth':
+        return mains_noise_synthetic, load_noise_synth_params(refpath)
+    else:
+        raise ValueError('Invalid schema', schema)
+
diff --git a/tools/e2e_test.c b/tools/e2e_test.c
new file mode 100644
index 0000000..935f70d
--- /dev/null
+++ b/tools/e2e_test.c
@@ -0,0 +1,111 @@
+
+#include <stdint.h>
+#include <math.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/fcntl.h>
+
+#include "freq_meas.h"
+#include "dsss_demod.h"
+
+typedef uint16_t adc_data_t;
+
+void handle_dsss_received(uint8_t data[static TRANSMISSION_SYMBOLS]) {
+    printf("data sequence received: [ ");
+    for (size_t i=0; i<TRANSMISSION_SYMBOLS; i++) {
+        printf("%+3d", ((data[i]&1) ? 1 : -1) * (data[i]>>1));
+        if (i+1 < TRANSMISSION_SYMBOLS)
+            printf(", ");
+    }
+    printf(" ]\n");
+}
+
+void print_usage(void);
+void print_usage() {
+    fprintf(stderr, "Usage: e2e_test [emulated_adc_data.bin]\n");
+}
+
+int main(int argc, char **argv) {
+    if (argc != 2) {
+        fprintf(stderr, "Error: Invalid arguments.\n");
+        print_usage();
+        return 1;
+    }
+
+    int fd = open(argv[1], O_RDONLY);
+    struct stat st;
+    if (fstat(fd, &st)) {
+        fprintf(stderr, "Error querying test data file size: %s\n", strerror(errno));
+        return 2;
+    }
+
+    if (st.st_size < 0 || st.st_size > 100000000) {
+        fprintf(stderr, "Error reading test data: too much test data (size=%zd)\n", st.st_size);
+        return 2;
+    }
+
+    if (st.st_size % sizeof(adc_data_t) != 0) {
+        fprintf(stderr, "Error reading test data: file size is not divisible by %zd (size=%zd)\n", sizeof(adc_data_t), st.st_size);
+        return 2;
+    }
+
+    char *buf = malloc(st.st_size);
+    if (!buf) {
+        fprintf(stderr, "Error allocating memory");
+        return 2;
+    }
+
+    const size_t n_samples = st.st_size / sizeof(adc_data_t);
+    fprintf(stderr, "Reading %zd samples test data...", n_samples);
+    ssize_t nread = 0;
+    while (nread < st.st_size) {
+        ssize_t rc = read(fd, buf + nread, st.st_size - nread);
+
+        if (rc == -EINTR || rc == -EAGAIN)
+            continue;
+
+        if (rc < 0) {
+            fprintf(stderr, "\nError reading test data: %s\n", strerror(errno));
+            return 2;
+        }
+        
+        if (rc == 0) {
+            fprintf(stderr, "\nError reading test data: Unexpected end of file\n");
+            return 2;
+        }
+
+        nread += rc;
+    }
+    fprintf(stderr, " done. Read %zd bytes.\n", nread);
+
+    adc_data_t *buf_d = (adc_data_t *)buf;
+
+    struct dsss_demod_state demod;
+    dsss_demod_init(&demod);
+
+    fprintf(stderr, "Starting simulation.\n");
+    size_t iterations = (n_samples-FMEAS_FFT_LEN)/(FMEAS_FFT_LEN/2);
+    for (size_t i=0; i<iterations; i++) {
+
+        /*
+        fprintf(stderr, "Iteration %zd/%zd\n", i, iterations);
+        */
+        float res = NAN;
+        int rc = adc_buf_measure_freq(buf_d + i*(FMEAS_FFT_LEN/2), &res);
+        if (rc)
+            printf("ERROR: Simulation error in iteration %zd at position %zd: %d\n", i, i*(FMEAS_FFT_LEN/2), rc);
+
+        dsss_demod_step(&demod, res, i);
+        /*
+        printf("%09zd %12f\n", i, res);
+        */
+    }
+    
+    free(buf);
+    return 0;
+}
diff --git a/tools/fft_window_header_gen.py b/tools/fft_window_header_gen.py
new file mode 100644
index 0000000..7df2ee3
--- /dev/null
+++ b/tools/fft_window_header_gen.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+
+import textwrap
+
+import scipy.signal as sig
+import numpy as np
+
+WINDOW_TYPES = [
+        'boxcar',
+        'triang',
+        'blackman',
+        'hamming',
+        'hann',
+        'bartlett',
+        'flattop',
+        'parzen',
+        'bohman',
+        'blackmanharris',
+        'nuttall',
+        'barthann',
+        'kaiser',
+        'gaussian',
+        'general_gaussian',
+        'slepian',
+        'dpss',
+        'chebwin',
+        'exponential',
+        'tukey',
+        ]
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('window', choices=WINDOW_TYPES, help='Type of window function to use')
+    parser.add_argument('n', type=int, help='Width of window in samples')
+    parser.add_argument('window_args', nargs='*', type=float,
+            help='''Window argument(s) if required. See https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.get_window.html#scipy.signal.get_window for details.''')
+    parser.add_argument('-v', '--variable', default='fft_window_table', help='Name for alias variable pointing to generated window')
+    args = parser.parse_args()
+    
+    print(f'/* FTT window table for {args.n} sample {args.window} window.')
+    if args.window_args:
+        print(f' * Window arguments were: ({" ,".join(str(arg) for arg in args.window_args)})')
+    print(f' */')
+    winargs = ''.join(f'_{arg:.4g}'.replace('.', 'F') for arg in args.window_args)
+    varname = f'fft_{args.n}_window_{args.window}{winargs}'
+    print(f'const float {varname}[{args.n}] = {{')
+
+    win = sig.get_window(args.window if not args.window_args else (args.window, *args.window_args),
+            Nx=args.n, fftbins=True)
+    par = ' '.join(f'{f:>013.8g},' for f in win)
+    print(textwrap.fill(par,
+        initial_indent=' '*4, subsequent_indent=' '*4,
+        width=120,
+        replace_whitespace=False, drop_whitespace=False))
+    print('};')
+    print()
+    print(f'const float * const {args.variable} __attribute__((weak)) = {varname};')
+
diff --git a/tools/fmeas_export_ocxo_2day.bin b/tools/fmeas_export_ocxo_2day.bin
new file mode 100644
index 0000000..c0cd8a8
--- /dev/null
+++ b/tools/fmeas_export_ocxo_2day.bin
diff --git a/tools/freq_meas_test.c b/tools/freq_meas_test.c
new file mode 100644
index 0000000..e2900ad
--- /dev/null
+++ b/tools/freq_meas_test.c
@@ -0,0 +1,106 @@
+
+#include <stdint.h>
+#include <math.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/fcntl.h>
+
+#include "freq_meas.h"
+
+void print_usage(void);
+
+void print_usage() {
+    fprintf(stderr, "Usage: freq_meas_test [test_data.bin]\n");
+}
+
+int main(int argc, char **argv) {
+    if (argc != 2) {
+        fprintf(stderr, "Error: Invalid arguments.\n");
+        print_usage();
+        return 1;
+    }
+
+    int fd = open(argv[1], O_RDONLY);
+    struct stat st;
+    if (fstat(fd, &st)) {
+        fprintf(stderr, "Error querying test data file size: %s\n", strerror(errno));
+        return 2;
+    }
+
+    if (st.st_size < 0 || st.st_size > 1000000) {
+        fprintf(stderr, "Error reading test data: too much test data (size=%zd)\n", st.st_size);
+        return 2;
+    }
+
+    if (st.st_size % sizeof(float) != 0) {
+        fprintf(stderr, "Error reading test data: file size is not divisible by %zd (size=%zd)\n", sizeof(float), st.st_size);
+        return 2;
+    }
+
+    char *buf = malloc(st.st_size);
+    if (!buf) {
+        fprintf(stderr, "Error allocating memory");
+        return 2;
+    }
+
+    fprintf(stderr, "Reading %zd samples test data...", st.st_size/sizeof(float));
+    ssize_t nread = 0;
+    while (nread < st.st_size) {
+        ssize_t rc = read(fd, buf + nread, st.st_size - nread);
+
+        if (rc == -EINTR || rc == -EAGAIN)
+            continue;
+
+        if (rc < 0) {
+            fprintf(stderr, "\nError reading test data: %s\n", strerror(errno));
+            return 2;
+        }
+        
+        if (rc == 0) {
+            fprintf(stderr, "\nError reading test data: Unexpected end of file\n");
+            return 2;
+        }
+
+        nread += rc;
+    }
+    fprintf(stderr, " done.\n");
+
+    const size_t n_samples = st.st_size / sizeof(float);
+    float *buf_f = (float *)buf;
+
+    int16_t *sim_adc_buf = calloc(sizeof(int16_t), n_samples);
+    if (!sim_adc_buf) {
+        fprintf(stderr, "Error allocating memory\n");
+        return 2;
+    }
+
+    fprintf(stderr, "Converting and truncating test data...");
+    for (size_t i=0; i<n_samples; i++)
+        /* Note on scaling: We can't simply scale by 0x8000 (1/2 full range) here. Our test data is nominally 1Vp-p but
+         * certain tests such as the interharmonics one can have some samples exceeding that range. */
+        sim_adc_buf[i] = buf_f[i] * (0x4000-1);
+    fprintf(stderr, " done.\n");
+
+    fprintf(stderr, "Starting simulation.\n");
+
+    size_t iterations = (n_samples-FMEAS_FFT_LEN)/(FMEAS_FFT_LEN/2);
+    for (size_t i=0; i<iterations; i++) {
+
+        fprintf(stderr, "Iteration %zd/%zd\n", i, iterations);
+        float res = NAN;
+        int rc = adc_buf_measure_freq(sim_adc_buf + i*(FMEAS_FFT_LEN/2), &res);
+        if (rc)
+            printf("ERROR: Simulation error in iteration %zd at position %zd: %d\n", i, i*(FMEAS_FFT_LEN/2), rc);
+
+        printf("%09zd %12f\n", i, res);
+    }
+    
+    free(buf);
+    free(sim_adc_buf);
+    return 0;
+}
diff --git a/tools/freq_meas_test_runner.py b/tools/freq_meas_test_runner.py
new file mode 100644
index 0000000..779922a
--- /dev/null
+++ b/tools/freq_meas_test_runner.py
@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+
+import os
+from os import path
+import subprocess
+import json
+
+import numpy as np
+np.set_printoptions(linewidth=240)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument(metavar='test_data_directory', dest='dir', help='Directory with test data .bin files')
+    default_binary = path.abspath(path.join(path.dirname(__file__), '../build/tools/freq_meas_test'))
+    parser.add_argument(metavar='test_binary', dest='binary', nargs='?', default=default_binary)
+    parser.add_argument('-d', '--dump', help='Write raw measurements to JSON file')
+    args = parser.parse_args()
+
+    bin_files = [ path.join(args.dir, d) for d in os.listdir(args.dir) if d.lower().endswith('.bin') ]
+
+    savedata = {}
+    for p in bin_files:
+        output = subprocess.check_output([args.binary, p], stderr=subprocess.DEVNULL)
+        measurements = np.array([ float(value) for _offset, value in [ line.split() for line in output.splitlines() ] ])
+        savedata[p] = list(measurements)
+
+        # Cut off first and last sample for mean and RMS calculations as these show boundary effects.
+        measurements = measurements[1:-1]
+        mean = np.mean(measurements)
+        rms = np.sqrt(np.mean(np.square(measurements - mean)))
+
+        print(f'{path.basename(p):<60}:    mean={mean:<8.4f}Hz rms={rms*1000:.3f}mHz')
+
+    if args.dump:
+        with open(args.dump, 'w') as f:
+            json.dump(savedata, f)
+
diff --git a/tools/gold_code_header_gen.py b/tools/gold_code_header_gen.py
new file mode 100644
index 0000000..fa98fce
--- /dev/null
+++ b/tools/gold_code_header_gen.py
@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+import sys
+import math
+import textwrap
+import contextlib
+
+import numpy as np
+import scipy.signal as sig
+
+# From https://github.com/mubeta06/python/blob/master/signal_processing/sp/gold.py
+preferred_pairs = {5:[[2],[1,2,3]], 6:[[5],[1,4,5]], 7:[[4],[4,5,6]],
+                        8:[[1,2,3,6,7],[1,2,7]], 9:[[5],[3,5,6]], 
+                        10:[[2,5,9],[3,4,6,8,9]], 11:[[9],[3,6,9]]}
+
+def gen_gold(seq1, seq2):
+    gold = [seq1, seq2]
+    for shift in range(len(seq1)):
+        gold.append(seq1 ^ np.roll(seq2, -shift))
+    return gold
+
+def gold(n):
+    n = int(n)
+    if not n in preferred_pairs:
+        raise KeyError('preferred pairs for %s bits unknown' % str(n))
+    t0, t1 = preferred_pairs[n]
+    (seq0, _st0), (seq1, _st1) = sig.max_len_seq(n, taps=t0), sig.max_len_seq(n, taps=t1)
+    return gen_gold(seq0, seq1)
+
+@contextlib.contextmanager
+def print_include_guards(macro_name):
+    print(f'#ifndef {macro_name}')
+    print(f'#define {macro_name}')
+    yield
+    print(f'#endif /* {macro_name} */')
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser(add_help=False)
+    parser.add_argument('n', type=int, choices=preferred_pairs, help='bit width of shift register. Generate 2**n + 1 sequences of length 2**n - 1.')
+    parser.add_argument('-v', '--variable', default='gold_code_table', help='Name for weak alias of generated table')
+    parser.add_argument('-h', '--header', action='store_true', help='Generate header file')
+    parser.add_argument('-c', '--source', action='store_true', help='Generate table source file')
+    args = parser.parse_args()
+
+    if not args.header != args.source:
+        print('Exactly one of --header and --source must be given.', file=sys.stderr)
+        sys.exit(1)
+
+    nbytes = math.ceil((2**args.n-1)/8)
+
+    if args.source:
+        print('/* THIS IS A GENERATED FILE. DO NOT EDIT! */')
+        print('#include <unistd.h>')
+        print('#include <stdint.h>')
+        print()
+        print(f'/* {args.n} bit gold sequences: {2**args.n+1} sequences of length {2**args.n-1} bit.')
+        print(f' *')
+        print(f' * Each code is packed left-aligned into {nbytes} bytes in big-endian byte order.')
+        print(f' */')
+        print(f'const uint8_t {args.variable}[{2**args.n+1}][{nbytes}] = {{')
+        for i, code in enumerate(gold(args.n)):
+            par = '{' + ' '.join(f'0x{d:02x},' for d in np.packbits(code)) + f'}}, /* {i: 3d} "{"".join(str(x) for x in code)}" */'
+            print(textwrap.fill(par, initial_indent=' '*4, subsequent_indent=' '*4, width=120))
+        print('};')
+        print()
+    else:
+        print('/* THIS IS A GENERATED FILE. DO NOT EDIT! */')
+        with print_include_guards(f'__GOLD_CODE_GENERATED_HEADER_{args.n}__'):
+            print(f'extern const uint8_t {args.variable}[{2**args.n+1}][{nbytes}];')
diff --git a/tools/grid_freq_psd_spl_108pt.json b/tools/grid_freq_psd_spl_108pt.json
new file mode 100644
index 0000000..5a0ff41
--- /dev/null
+++ b/tools/grid_freq_psd_spl_108pt.json
@@ -0,0 +1 @@
+{"x_spec": [3.2595692805152726e-05, 5.0, 613575], "t": [3.2595692805152726e-05, 3.2595692805152726e-05, 3.2595692805152726e-05, 3.2595692805152726e-05, 0.0001423024947075771, 0.00015800362803968106, 0.00017543716661470822, 0.00019479425764873777, 0.0002162871388378975, 0.00024015146540428407, 0.00026664889389955537, 0.00029606995109590574, 0.00032873721941990017, 0.0003650088738553592, 0.0004052826090950758, 0.00045000000000000004, 0.000499651343175437, 0.0005547810327489297, 0.0006159935292916862, 0.0006839599873288199, 0.0007594256141046668, 0.0008432178402871724, 0.0009362553921977272, 0.0010395583650374223, 0.0011542594075560205, 0.001281616140796111, 0.0014230249470757708, 0.001580036280396809, 0.0017543716661470824, 0.0019479425764873776, 0.002162871388378975, 0.0024015146540428403, 0.002666488938995554, 0.002960699510959057, 0.0032873721941990056, 0.0036500887385535925, 0.004052826090950754, 0.0045000000000000005, 0.00499651343175437, 0.005547810327489296, 0.006159935292916869, 0.0068395998732882, 0.007594256141046669, 0.008432178402871724, 0.009362553921977271, 0.010395583650374221, 0.011542594075560205, 0.012816161407961109, 0.014230249470757707, 0.01580036280396809, 0.017543716661470823, 0.01947942576487376, 0.02162871388378975, 0.024015146540428405, 0.026664889389955565, 0.02960699510959057, 0.03287372194199005, 0.036500887385535925, 0.04052826090950754, 0.045, 0.0499651343175437, 0.05547810327489296, 0.06159935292916863, 0.06839599873288206, 0.07594256141046668, 0.08432178402871732, 0.09362553921977272, 0.10395583650374222, 0.11542594075560206, 0.12816161407961107, 0.14230249470757705, 0.15800362803968088, 0.1754371666147082, 0.1947942576487376, 0.21628713883789774, 0.24015146540428406, 0.26664889389955565, 0.2960699510959057, 0.32873721941990053, 0.36500887385535924, 0.40528260909507535, 0.45, 0.499651343175437, 0.5547810327489296, 0.6159935292916868, 0.6839599873288206, 0.7594256141046669, 0.8432178402871732, 0.9362553921977271, 1.0395583650374223, 1.1542594075560206, 1.2816161407961109, 1.4230249470757708, 1.5800362803968104, 1.7543716661470823, 1.9479425764873777, 2.162871388378975, 2.4015146540428405, 2.6664889389955535, 2.960699510959057, 3.287372194199002, 3.6500887385535927, 4.052826090950758, 4.5, 5.0, 5.0, 5.0, 5.0], "c": [0.7720161468716866, -0.5547528253056444, 0.30706059086000753, 0.19422577014134906, -1.1954636661840032, 0.9215976941641111, -0.6668136393976918, -1.341269161156733, -0.16311330594842666, -1.7639636752234251, -1.238385544822954, -0.32649555618555554, -0.03086589610280171, -2.358195657381619, -0.5759152419849985, 0.1892225800004134, -1.8122889670546236, -0.8109120798216202, -0.5500991736738969, -4.680192969256771, -2.8007700704649876, 0.16866469558571784, -1.1040811840849307, -3.0243574268705546, -4.018139927365795, -4.100581028618109, -0.556354762846191, -7.414377514669229, 1.36396325920194, -6.002559557058508, -2.2113451390305365, -4.578944771104116, -4.372644849632638, -3.945339124673235, -4.778747958903158, -2.370174137632325, -5.7372466088109295, -4.707506574819875, -4.834404729330929, -5.005244244061701, -5.82644896783577, -4.717966026411524, -6.146374820241562, -4.972788381244952, -5.854957092953355, -5.702174935205885, -6.222035857079607, -6.2128389666872, -6.212821706753751, -6.253599689326325, -6.681685577659057, -6.372364384360678, -6.771223202540934, -6.856809137231159, -6.986412256164045, -7.190466178818742, -7.577896455149433, -7.515731696006047, -7.598155006351761, -7.824526916149126, -8.141496591776512, -8.36794927682997, -8.80307396767114, -8.828816533544659, -9.357524260470413, -9.658130054343863, -10.005768472049466, -10.499801262514108, -11.028689820560558, -11.413688641742898, -11.906162042727946, -12.232342460719975, -12.438432746733596, -13.088338100203112, -12.308710772618745, -11.685074853925329, -11.397838681243094, -12.265219694936695, -13.600359694898529, -14.031425961884718, -12.236885080485473, -13.527508426900974, -13.698402018452601, -13.397911198962568, -14.144410560196603, -13.905769594095293, -14.410874830544122, -14.531727635304264, -14.59275291853806, -14.35404826562502, -14.58670053318149, -14.432515268864977, -14.363428024828353, -14.429222027493264, -14.73947634127499, -14.717315405960353, -14.678539669792505, -14.825278423641382, -14.80936417940876, -14.943375264882789, -14.680885181815674, -14.54841244844906, -14.634365225950589, -14.609444790868906, 0.0, 0.0, 0.0, 0.0], "k": 3}
\ No newline at end of file
diff --git a/tools/hum_generator.py b/tools/hum_generator.py
new file mode 100644
index 0000000..fbcabac
--- /dev/null
+++ b/tools/hum_generator.py
@@ -0,0 +1,111 @@
+#!/usr/bin/env python
+# coding: utf-8
+
+import binascii
+import struct
+
+import numpy as np
+import pydub
+
+from dsss_demod_test_waveform_gen import load_noise_gen, modulate as dsss_modulate
+
+np.set_printoptions(linewidth=240)
+
+def generate_noisy_signal(
+        test_data=32,
+        test_nbits=5,
+        test_decimation=10,
+        test_signal_amplitude=20e-3,
+        noise_level=10e-3,
+        noise_spec='synth://grid_freq_psd_spl_108pt.json',
+        seed=0):
+
+    #test_data = np.random.RandomState(seed=0).randint(0, 2 * (2**test_nbits), test_duration)
+    #test_data = np.array([0, 1, 2, 3] * 50)
+    if isinstance(test_data, int):
+        test_data = np.array(range(test_data))
+
+
+    signal = np.repeat(dsss_modulate(test_data, test_nbits) * 2.0 - 1, test_decimation)
+
+    noise_gen, noise_params = load_noise_gen(noise_spec)
+    noise = noise_gen(seed, len(signal), **noise_params)
+    return np.absolute(noise + signal*test_signal_amplitude)
+
+def write_raw_frequencies_bin(outfile, **kwargs):
+    with open(outfile, 'wb') as f:
+        for x in generate_noisy_signal(**kwargs):
+            f.write(struct.pack('f', x))
+
+def synthesize_sine(freqs, freqs_sampling_rate=10.0, output_sampling_rate=44100):
+    duration = len(freqs) / freqs_sampling_rate # seconds
+    afreq_out = np.interp(np.linspace(0, duration, int(duration*output_sampling_rate)), np.linspace(0, duration, len(freqs)), freqs)
+    return np.sin(np.cumsum(2*np.pi * afreq_out / output_sampling_rate))
+
+def write_flac(filename, signal, sampling_rate=44100):
+    signal -= np.min(signal)
+    signal /= np.max(signal)
+    signal -= 0.5
+    signal *= 2**16 - 1
+    le_bytes = signal.astype(np.int16).tobytes()
+    seg = pydub.AudioSegment(data=le_bytes, sample_width=2, frame_rate=sampling_rate, channels=1)
+    seg.export(filename, format='flac')
+
+def write_synthetic_hum_flac(filename, output_sampling_rate=44100, freqs_sampling_rate=10.0, **kwargs):
+    signal = generate_noisy_signal(**kwargs)
+    print(signal)
+    write_flac(filename, synthesize_sine(signal, freqs_sampling_rate, output_sampling_rate),
+            sampling_rate=output_sampling_rate)
+
+def emulate_adc_signal(adc_bits=12, adc_offset=0.4, adc_amplitude=0.25, freq_sampling_rate=10.0, output_sampling_rate=1000, **kwargs):
+    signal = synthesize_sine(generate_noisy_signal(), freq_sampling_rate, output_sampling_rate)
+    signal = signal*adc_amplitude + adc_offset
+    smin, smax = np.min(signal), np.max(signal)
+    if smin < 0.0 or smax > 1.0:
+        raise UserWarning('Amplitude or offset too large: Signal out of bounds with min/max [{smin}, {smax}] of ADC range')
+    signal *= 2**adc_bits -1
+    return signal
+
+def save_adc_signal(fn, signal, dtype=np.uint16):
+    with open(fn, 'wb') as f:
+        f.write(signal.astype(dtype).tobytes())
+
+def write_emulated_adc_signal_bin(filename, **kwargs):
+    save_adc_signal(filename, emulate_adc_signal(**kwargs))
+
+def hum_cmd(args):
+    write_synthetic_hum_flac(args.out_flac,
+            output_sampling_rate=args.audio_sampling_rate,
+            freqs_sampling_rate=args.frequency_sampling_rate,
+            test_data = np.array(list(binascii.unhexlify(args.data))),
+            test_nbits = args.symbol_bits,
+            test_decimation = args.decimation,
+            test_signal_amplitude = args.signal_level/1e3,
+            noise_level = args.noise_level/1e3,
+            noise_spec=args.noise_spec,
+            seed = args.random_seed)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    cmd_parser = parser.add_subparsers(required=True)
+    hum_parser = cmd_parser.add_parser('hum', help='Generated artificial modulated mains hum')
+    # output parameters
+    hum_parser.add_argument('-a', '--audio-sampling-rate', type=int, default=44100)
+
+    # modulation parameters
+    hum_parser.add_argument('-f', '--frequency-sampling-rate', type=float, default=10.0*100/128)
+    hum_parser.add_argument('-b', '--symbol-bits', type=int, default=5, help='bits per symbol (excluding sign bit)')
+    hum_parser.add_argument('-n', '--noise-level', type=float, default=1.0, help='Scale synthetic noise level')
+    hum_parser.add_argument('-s', '--signal-level', type=float, default=20.0, help='Synthetic noise level in mHz')
+    hum_parser.add_argument('-d', '--decimation', type=int, default=10, help='DSSS modulation decimation in frequency measurement cycles')
+    hum_parser.add_argument('-r', '--random-seed', type=int, default=0)
+    hum_parser.add_argument('--noise-spec', type=str, default='synth://grid_freq_psd_spl_108pt.json')
+    hum_parser.add_argument('out_flac', metavar='out.flac', help='FLAC output file')
+    hum_parser.add_argument('data', help='modulation data hex string')
+    hum_parser.set_defaults(func=hum_cmd)
+
+    args = parser.parse_args()
+    args.func(args)
+    
diff --git a/tools/ldparser.py b/tools/ldparser.py
new file mode 100644
index 0000000..c620fe2
--- /dev/null
+++ b/tools/ldparser.py
@@ -0,0 +1,126 @@
+
+import sys
+
+import pyparsing as pp
+from pyparsing import pyparsing_common as ppc
+
+LPAREN, RPAREN, LBRACE, RBRACE, LBROK, RBROK, COLON, SEMICOLON, EQUALS, COMMA = map(pp.Suppress, '(){}<>:;=,')
+
+parse_suffix_int = lambda lit: int(lit[:-1]) * (10**(3*(1 + 'kmgtpe'.find(lit[-1].lower()))))
+si_suffix = pp.oneOf('k m g t p e', caseless=True)
+
+numeric_literal = pp.Regex('0x[0-9a-fA-F]+').setName('hex int').setParseAction(pp.tokenMap(int, 16)) \
+        | (pp.Regex('[0-9]+[kKmMgGtTpPeE]')).setName('size int').setParseAction(pp.tokenMap(parse_suffix_int)) \
+        | pp.Word(pp.nums).setName('int').setParseAction(pp.tokenMap(int))
+access_def = pp.Regex('[rR]?[wW]?[xX]?').setName('access literal').setParseAction(pp.tokenMap(str.lower))
+
+origin_expr = pp.Suppress(pp.CaselessKeyword('ORIGIN')) + EQUALS + numeric_literal
+length_expr = pp.Suppress(pp.CaselessKeyword('LENGTH')) + EQUALS + numeric_literal
+mem_expr = pp.Group(ppc.identifier + LPAREN + access_def + RPAREN + COLON + origin_expr + COMMA + length_expr)
+mem_contents = pp.ZeroOrMore(mem_expr)
+
+mem_toplevel = pp.CaselessKeyword("MEMORY") + pp.Group(LBRACE + pp.Optional(mem_contents, []) + RBRACE)
+
+glob = pp.Word(pp.alphanums + '._*')
+match_expr = pp.Forward()
+assignment = pp.Forward()
+funccall = pp.Group(pp.Word(pp.alphas + '_') + LPAREN + (assignment | numeric_literal | match_expr | glob | ppc.identifier) + RPAREN + pp.Optional(SEMICOLON))
+value = numeric_literal | funccall | ppc.identifier | '.'
+formula = (value + pp.oneOf('+ = * / %') + value) | value
+# suppress stray semicolons
+assignment << (SEMICOLON | pp.Group((ppc.identifier | '.') + EQUALS + (formula | value) + pp.Optional(SEMICOLON)))
+match_expr << (glob + LPAREN + pp.OneOrMore(funccall | glob) + RPAREN)
+
+section_contents = pp.ZeroOrMore(assignment | funccall | match_expr);
+
+section_name = pp.Regex('\.[a-zA-Z0-9_.]+')
+section_def = pp.Group(section_name + pp.Optional(numeric_literal) + COLON + LBRACE + pp.Group(section_contents) +
+        RBRACE + pp.Optional(RBROK + ppc.identifier + pp.Optional('AT' + RBROK + ppc.identifier)))
+sec_contents = pp.ZeroOrMore(section_def | assignment)
+
+sections_toplevel = pp.Group(pp.CaselessKeyword("SECTIONS").suppress() + LBRACE + sec_contents + RBRACE)
+
+toplevel_elements = mem_toplevel | funccall | sections_toplevel | assignment
+ldscript = pp.Group(pp.ZeroOrMore(toplevel_elements))
+ldscript.ignore(pp.cppStyleComment)
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('linker_script', type=argparse.FileType('r'))
+    args = parser.parse_args()
+
+    #print(mem_expr.parseString('FLASH (rx) : ORIGIN = 0x0800000, LENGTH = 512K', parseAll=True))
+    # print(ldscript.parseString('''
+    #     /* Entry Point */
+    #     ENTRY(Reset_Handler)
+    #
+    #     /* Highest address of the user mode stack */
+    #     _estack = 0x20020000;    /* end of RAM */
+    #     /* Generate a link error if heap and stack don't fit into RAM */
+    #     _Min_Heap_Size = 0x200;;      /* required amount of heap  */
+    #     _Min_Stack_Size = 0x400;; /* required amount of stack */
+    #     ''', parseAll=True))
+
+    print(ldscript.parseFile(args.linker_script, parseAll=True))
+    #print(funccall.parseString('KEEP(*(.isr_vector))'))
+    #print(section_contents.parseString('''
+    #        . = ALIGN(4);
+    #        KEEP(*(.isr_vector)) /* Startup code */
+    #        . = ALIGN(4);
+    #        ''', parseAll=True))
+
+    #print(section_def.parseString('''
+    #      .text :
+    #      {
+    #        . = ALIGN(4);
+    #        *(.text)           /* .text sections (code) */
+    #        *(.text*)          /* .text* sections (code) */
+    #        *(.glue_7)         /* glue arm to thumb code */
+    #        *(.glue_7t)        /* glue thumb to arm code */
+    #        *(.eh_frame)
+    #
+    #        KEEP (*(.init))
+    #        KEEP (*(.fini))
+    #
+    #        . = ALIGN(4);
+    #        _etext = .;        /* define a global symbols at end of code */
+    #      } >FLASH
+    #      ''', parseAll=True))
+
+    #print(section_def.parseString('.ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH', parseAll=True))
+
+    #print(assignment.parseString('__preinit_array_start = .', parseAll=True))
+    #print(assignment.parseString('a = 23', parseAll=True))
+    #print(funccall.parseString('foo (a=23)', parseAll=True))
+    #print(funccall.parseString('PROVIDE_HIDDEN (__preinit_array_start = .);', parseAll=True))
+    #print(section_def.parseString('''
+    #      .preinit_array     :
+    #      {
+    #        PROVIDE_HIDDEN (__preinit_array_start = .);
+    #        KEEP (*(.preinit_array*))
+    #        PROVIDE_HIDDEN (__preinit_array_end = .);
+    #        } >FLASH''', parseAll=True))
+    #print(match_expr.parseString('*(SORT(.init_array.*))', parseAll=True))
+    #print(funccall.parseString('KEEP (*(SORT(.init_array.*)))', parseAll=True))
+    #print(section_def.parseString('''
+    #      .init_array :
+    #      {
+    #        PROVIDE_HIDDEN (__init_array_start = .);
+    #        KEEP (*(SORT(.init_array.*)))
+    #        KEEP (*(.init_array*))
+    #        PROVIDE_HIDDEN (__init_array_end = .);
+    #      } >FLASH
+    #      ''', parseAll=True))
+
+    #print(match_expr.parseString('*(.ARM.extab* .gnu.linkonce.armextab.*)', parseAll=True))
+    #print(formula.parseString('. + _Min_Heap_Size', parseAll=True))
+    #print(assignment.parseString('. = . + _Min_Heap_Size;', parseAll=True))
+    #print(sections_toplevel.parseString('''
+    #    SECTIONS
+    #    {
+    #      .ARMattributes : {  }
+    #    }
+    #      ''', parseAll=True))
+    #sys.exit(0)
+
diff --git a/tools/linkmem.py b/tools/linkmem.py
new file mode 100644
index 0000000..934a571
--- /dev/null
+++ b/tools/linkmem.py
@@ -0,0 +1,276 @@
+
+import tempfile
+import os
+from os import path
+import sys
+import re
+import subprocess
+from contextlib import contextmanager
+from collections import defaultdict
+import colorsys
+
+import cxxfilt
+from elftools.elf.elffile import ELFFile
+from elftools.elf.enums import ENUM_ST_SHNDX
+from elftools.elf.descriptions import describe_symbol_type, describe_sh_type
+import libarchive
+import matplotlib.cm
+
+@contextmanager
+def chdir(newdir):
+    old_cwd = os.getcwd()
+    try:
+        os.chdir(newdir)
+        yield
+    finally:
+        os.chdir(old_cwd)
+
+def keep_last(it, first=None):
+    last = first
+    for elem in it:
+        yield last, elem
+        last = elem
+
+def delim(start, end, it, first_only=True):
+    found = False
+    for elem in it:
+        if end(elem):
+            if first_only:
+                return
+            found = False
+        elif start(elem):
+            found = True
+        elif found:
+            yield elem
+
+def delim_prefix(start, end, it):
+    yield from delim(lambda l: l.startswith(start), lambda l: end is not None and l.startswith(end), it)
+
+def trace_source_files(linker, cmdline, trace_sections=[], total_sections=['.text', '.data', '.rodata']):
+    with tempfile.TemporaryDirectory() as tempdir:
+        out_path = path.join(tempdir, 'output.elf')
+        output = subprocess.check_output([linker, '-o', out_path, f'-Wl,--print-map', *cmdline])
+        lines = [ line.strip() for line in output.decode().splitlines() ]
+        # FIXME also find isr vector table references
+
+        defs = {}
+        objs = defaultdict(lambda: 0)
+        aliases = {}
+        sec_name = None
+        last_loc = None
+        last_sym = None
+        line_cont = None
+        for last_line, line in keep_last(delim_prefix('Linker script and memory map', 'OUTPUT', lines), first=''):
+            if not line or line.startswith('LOAD '):
+                sec_name = None
+                continue
+
+            # first part of continuation line
+            if m := re.match('^(\.[0-9a-zA-Z-_.]+)$', line):
+                line_cont = line
+                sec_name = None
+                continue
+
+            if line_cont:
+                line = line_cont + ' ' + line
+                line_cont = None
+
+            # -ffunction-sections/-fdata-sections section
+            if m := re.match('^(\.[0-9a-zA-Z-_.]+)\.([0-9a-zA-Z-_.]+)\s+(0x[0-9a-f]+)\s+(0x[0-9a-f]+)\s+(\S+)$', line):
+                sec, sym, loc, size, obj = m.groups()
+                *_, sym = sym.rpartition('.')
+                sym = cxxfilt.demangle(sym)
+                size = int(size, 16)
+                obj = path.abspath(obj)
+
+                if sec not in total_sections:
+                    size = 0
+
+                objs[obj] += size
+                defs[sym] = (sec, size, obj)
+
+                sec_name, last_loc, last_sym = sec, loc, sym
+                continue
+            
+            # regular (no -ffunction-sections/-fdata-sections) section
+            if m := re.match('^(\.[0-9a-zA-Z-_]+)\s+(0x[0-9a-f]+)\s+(0x[0-9a-f]+)\s+(\S+)$', line):
+                sec, _loc, size, obj = m.groups()
+                size = int(size, 16)
+                obj = path.abspath(obj)
+
+                if sec in total_sections:
+                    objs[obj] += size
+
+                sec_name = sec
+                last_loc, last_sym = None, None
+                continue
+            
+            # symbol def
+            if m := re.match('^(0x[0-9a-f]+)\s+(\S+)$', line):
+                loc, sym = m.groups()
+                sym = cxxfilt.demangle(sym)
+                loc = int(loc, 16)
+                if sym in defs:
+                    continue
+
+                if loc == last_loc:
+                    assert last_sym is not None
+                    aliases[sym] = last_sym
+                else:
+                    assert sec_name
+                    defs[sym] = (sec_name, None, obj)
+                    last_loc, last_sym = loc, sym
+
+                continue
+
+        refs = defaultdict(lambda: set())
+        for sym, (sec, size, obj) in defs.items():
+            fn, _, member = re.match('^([^()]+)(\((.+)\))?$', obj).groups()
+            fn = path.abspath(fn)
+
+            if member:
+                subprocess.check_call(['ar', 'x', '--output', tempdir, fn, member])
+                fn = path.join(tempdir, member)
+
+            with open(fn, 'rb') as f:
+                elf = ELFFile(f)
+
+                symtab = elf.get_section_by_name('.symtab')
+                
+                symtab_demangled = { cxxfilt.demangle(nsym.name).replace(' ', ''): i
+                        for i, nsym in enumerate(symtab.iter_symbols()) }
+
+                s = set()
+                sec_map = { sec.name: i for i, sec in enumerate(elf.iter_sections()) }
+                matches = [ i for name, i in sec_map.items() if re.match(f'\.rel\..*\.{sym}', name) ]
+                if matches:
+                    sec = elf.get_section(matches[0])
+                    for reloc in sec.iter_relocations():
+                        refsym = symtab.get_symbol(reloc['r_info_sym'])
+                        name = refsym.name if refsym.name else elf.get_section(refsym['st_shndx']).name.split('.')[-1]
+                        s.add(name)
+                refs[sym] = s
+
+                for tsec in trace_sections:
+                    matches = [ i for name, i in sec_map.items() if name == f'.rel{tsec}' ]
+                    s = set()
+                    if matches:
+                        sec = elf.get_section(matches[0])
+                        for reloc in sec.iter_relocations():
+                            refsym = symtab.get_symbol(reloc['r_info_sym'])
+                            s.add(refsym.name)
+                    refs[tsec.replace('.', '_')] |= s
+
+        return objs, aliases, defs, refs
+
+@contextmanager
+def wrap(leader='', print=print, left='{', right='}'):
+    print(leader, left)
+    yield lambda *args, **kwargs: print('   ', *args, **kwargs)
+    print(right)
+
+def mangle(name):
+    return re.sub('[^a-zA-Z0-9_]', '_', name)
+
+hexcolor = lambda r, g, b, *_a: f'#{int(r*255):02x}{int(g*255):02x}{int(b*255):02x}'
+def vhex(val):
+    r,g,b,_a = matplotlib.cm.viridis(1.0-val)
+    fc = hexcolor(r, g, b)  
+    h,s,v = colorsys.rgb_to_hsv(r,g,b)
+    cc = '#000000' if v > 0.8 else '#ffffff'
+    return fc, cc
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--trace-sections', type=str, action='append', default=[])
+    parser.add_argument('--trim-stubs', type=str, action='append', default=[])
+    parser.add_argument('--highlight-subdirs', type=str, default=None)
+    parser.add_argument('linker_binary')
+    parser.add_argument('linker_args', nargs=argparse.REMAINDER)
+    args = parser.parse_args()
+
+    trace_sections = args.trace_sections
+    trace_sections_mangled = { sec.replace('.', '_') for sec in trace_sections }
+    objs, aliases, syms, refs = trace_source_files(args.linker_binary, args.linker_args, trace_sections)
+
+    clusters = defaultdict(lambda: [])
+    for sym, (sec, size, obj) in syms.items():
+        clusters[obj].append((sym, sec, size))
+
+    max_ssize = max(size or 0 for _sec, size, _obj in syms.values())
+    max_osize = max(objs.values())
+
+    subdir_prefix = path.abspath(args.highlight_subdirs) + '/' if args.highlight_subdirs else '### NO HIGHLIGHT ###'
+    first_comp = lambda le_path: path.dirname(le_path).partition(os.sep)[0]
+    subdir_colors = sorted({ first_comp(obj[len(subdir_prefix):]) for obj in objs if obj.startswith(subdir_prefix) })
+    subdir_colors = { path: hexcolor(*matplotlib.cm.Pastel1(i/len(subdir_colors))) for i, path in enumerate(subdir_colors) }
+
+    subdir_sizes = defaultdict(lambda: 0)
+    for obj, size in objs.items():
+        if not isinstance(size, int):
+            continue
+        if obj.startswith(subdir_prefix):
+            subdir_sizes[first_comp(obj[len(subdir_prefix):])] += size
+        else:
+            subdir_sizes['<others>'] += size
+
+    print('Subdir sizes:', file=sys.stderr)
+    for subdir, size in sorted(subdir_sizes.items(), key=lambda x: x[1]):
+        print(f'{subdir:>20}: {size:>6,d} B', file=sys.stderr)
+
+    def lookup_highlight(path):
+        if args.highlight_subdirs:
+            if obj.startswith(subdir_prefix):
+                highlight_head = first_comp(path[len(subdir_prefix):])
+                return subdir_colors[highlight_head], highlight_head
+            else:
+                return '#e0e0e0', None
+        else:
+            return '#ddf7f4', None
+
+    with wrap('digraph G', print) as lvl1print:
+        print('size="23.4,16.5!";')
+        print('graph [fontsize=40];')
+        print('node [fontsize=40];')
+        #print('ratio="fill";')
+
+        print('rankdir=LR;')
+        print('ranksep=5;')
+        print('nodesep=0.2;')
+        print()
+
+        for i, (obj, obj_syms) in enumerate(clusters.items()):
+            with wrap(f'subgraph cluster_{i}', lvl1print) as lvl2print:
+                print('style = "filled";')
+                highlight_color, highlight_head = lookup_highlight(obj)
+                print(f'bgcolor = "{highlight_color}";')
+                print('pencolor = none;')
+                fc, cc = vhex(objs[obj]/max_osize)
+                highlight_subdir_part = f'<font face="carlito" color="{cc}" point-size="40">{highlight_head} / </font>' if highlight_head else ''
+                lvl2print(f'label = <<table border="0"><tr><td border="0" cellpadding="5" bgcolor="{fc}">'
+                          f'{highlight_subdir_part}'
+                          f'<font face="carlito" color="{cc}"><b>{path.basename(obj)} ({objs[obj]}B)</b></font>'
+                          f'</td></tr></table>>;')
+                lvl2print()
+                for sym, sec, size in obj_syms:
+                    has_size = isinstance(size, int) and size > 0
+                    size_s = f' ({size}B)' if has_size else ''
+                    fc, cc = vhex(size/max_ssize) if has_size else ('#ffffff', '#000000')
+                    shape = 'box' if sec == '.text' else 'oval'
+                    lvl2print(f'{mangle(sym)}[label = "{sym}{size_s}", style="rounded,filled", shape="{shape}", fillcolor="{fc}", fontname="carlito", fontcolor="{cc}" color=none];')
+            lvl1print()
+
+        edges = set()
+        for start, ends in refs.items():
+            for end in ends:
+                end = aliases.get(end, end)
+                if (start in syms or start in trace_sections_mangled) and end in syms:
+                    edges.add((start, end))
+
+        for start, end in edges:
+            lvl1print(f'{mangle(start)} -> {mangle(end)} [style="bold", color="#333333"];')
+
+        for sec in trace_sections:
+            lvl1print(f'{sec.replace(".", "_")} [label = "section {sec}", shape="box", style="filled,bold"];')
+
diff --git a/tools/linksize.py b/tools/linksize.py
new file mode 100644
index 0000000..c41a951
--- /dev/null
+++ b/tools/linksize.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+def parse_linker_script(data):
+    pass
+
+def link(groups):
+    defined_symbols = {}
+    undefined_symbols = set()
+    for group, files in groups:
+        while True:
+            found_something = False
+
+            for fn in files:
+                symbols = load_symbols(fn)
+                for symbol in symbols:
+                    if symbol in defined_symbols:
+
+            if not group or not found_something:
+                break
+
+
+if __name__ == '__main__':
+
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-T', '--script', type=str, help='Linker script to use')
+    parser.add_argument('-o', '--output', type=str, help='Output file to produce')
+    args, rest = parser.parse_known_intermixed_args()
+    print(rest)
+
+    addprefix = lambda *xs: [ prefix + opt for opt in xs for prefix in ('', '-Wl,') ]
+    START_GROUP = addprefix('-(', '--start-group')
+    END_GROUP = addprefix('-)', '--end-group')
+    GROUP_OPTS = [*START_GROUP, *END_GROUP]
+    input_files = [ arg for arg in rest if not arg.startswith('-') or arg in GROUP_OPTS ]
+
+    def input_file_iter(input_files):
+        group = False
+        files = []
+        for arg in input_files:
+            if arg in START_GROUP:
+                assert not group
+
+                if files:
+                    yield False, files # nested -Wl,--start-group
+                group, files = True, []
+
+            elif arg in END_GROUP:
+                assert group # missing -Wl,--start-group
+                if files:
+                    yield True, files
+                group, files = False, []
+
+            else:
+                files.append(arg)
+
+        assert not group # missing -Wl,--end-group
+        if files:
+            yield False, files
+
+
+
diff --git a/tools/linktracer.py b/tools/linktracer.py
new file mode 100644
index 0000000..0c53a60
--- /dev/null
+++ b/tools/linktracer.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+
+import re
+import subprocess
+import tempfile
+import pprint
+
+ARCHIVE_RE = r'([^(]*)(\([^)]*\))?'
+
+def trace_source_files(linker, cmdline):
+    with tempfile.NamedTemporaryFile() as mapfile:
+        output = subprocess.check_output([linker, f'-Wl,--Map={mapfile.name}', *cmdline])
+
+        # intentionally use generator here
+        idx = 0 
+        lines = [ line.rstrip() for line in mapfile.read().decode().splitlines() if line.strip() ]
+        
+        for idx, line in enumerate(lines[idx:], start=idx):
+            #print('Dropping', line)
+            if line == 'Linker script and memory map':
+                break
+
+        idx += 1
+        objects = []
+        symbols = {}
+        sections = {}
+        current_object = None
+        last_offset = None
+        last_symbol = None
+        cont_sec = None
+        cont_ind = None
+        current_section = None
+        for idx, line in enumerate(lines[idx:], start=idx):
+            print(f'Processing >{line}')
+            if line.startswith('LOAD'):
+                _load, obj = line.split()
+                objects.append(obj)
+                continue
+
+            if line.startswith('OUTPUT'):
+                break
+
+            m = re.match(r'^( ?)([^ ]+)? +(0x[0-9a-z]+) +(0x[0-9a-z]+)?(.*)?$', line)
+            if m is None:
+                m = re.match(r'^( ?)([^ ]+)?$', line)
+                if m:
+                    cont_ind, cont_sec = m.groups()
+                else:
+                    cont_ind, cont_sec = None, None
+                last_offset, last_symbol = None, None
+                continue
+            indent, sec, offx, size, sym_or_src = m.groups()
+            if sec is None:
+                sec = cont_sec
+                ind = cont_ind
+            cont_sec = None
+            cont_ind = None
+            print(f'vals: indent={indent} sec={sec} offx={offx} size={size} sym_or_src={sym_or_src}')
+            if not re.match('^[a-zA-Z_0-9<>():*]+$', sym_or_src):
+                continue
+
+            if indent == '':
+                print(f'Section: {sec} 0x{size:x}')
+                current_section = sec
+                sections[sec] = size
+                last_offset = None
+                last_symbol = None
+                continue
+
+            if offx is not None:
+                offx = int(offx, 16)
+            if size is not None:
+                size = int(size, 16)
+
+            if size is not None and sym_or_src is not None:
+                # archive/object line
+                archive, _member = re.match(ARCHIVE_RE, sym_or_src).groups()
+                current_object = archive
+                last_offset = offx
+            else:
+                if sym_or_src is not None:
+                    assert size is None
+                    if last_offset is not None:
+                        last_size = offx - last_offset
+                        symbols[last_symbol] = (last_size, current_section)
+                        print(f'Symbol: {last_symbol} 0x{last_size:x} @{current_section}')
+                    last_offset = offx
+                    last_symbol = sym_or_src
+
+        idx += 1
+
+        for idx, line in enumerate(lines[idx:], start=idx):
+            if line == 'Cross Reference Table':
+                break
+
+        idx += 1
+
+        # map which symbol was pulled from which object in the end
+        used_defs = {}
+        for line in lines:
+            *left, right = line.split()
+
+            archive, _member = re.match(ARCHIVE_RE, right).groups()
+            if left:
+                used_defs[''.join(left)] = archive
+
+        #pprint.pprint(symbols)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('linker_binary')
+    parser.add_argument('linker_args', nargs=argparse.REMAINDER)
+    args = parser.parse_args()
+
+    source_files = trace_source_files(args.linker_binary, args.linker_args)
+
diff --git a/tools/mapparse.py b/tools/mapparse.py
new file mode 100644
index 0000000..c1f460a
--- /dev/null
+++ b/tools/mapparse.py
@@ -0,0 +1,129 @@
+
+import re
+from collections import defaultdict, namedtuple
+
+Section = namedtuple('Section', ['name', 'offset', 'objects'])
+ObjectEntry = namedtuple('ObjectEntry', ['filename', 'object', 'offset', 'size'])
+FileEntry = namedtuple('FileEntry', ['section', 'object', 'offset', 'length'])
+
+class Memory:
+    def __init__(self, name, origin, length, attrs=''):
+        self.name, self.origin, self.length, self.attrs = name, origin, length, attrs
+        self.sections = {}
+        self.files = defaultdict(lambda: [])
+        self.totals = defaultdict(lambda: 0)
+
+    def add_toplevel(self, name, offx, length):
+        self.sections[name] = Section(offx, length, [])
+
+    def add_obj(self, name, offx, length, fn, obj):
+        base_section, sep, subsec = name[1:].partition('.')
+        base_section = '.'+base_section
+        if base_section in self.sections:
+            sec = secname, secoffx, secobjs = self.sections[base_section]
+            secobjs.append(ObjectEntry(fn, obj, offx, length))
+        else:
+            sec = None
+        self.files[fn].append(FileEntry(sec, obj, offx, length))
+        self.totals[fn] += length
+
+class MapFile:
+    def __init__(self, s):
+        self._lines = s.splitlines()
+        self.memcfg = {}
+        self.defaultmem = Memory('default', 0, 0xffffffffffffffff)
+        self._parse()
+
+    def __getitem__(self, offx_or_name):
+        ''' Lookup a memory area by name or address '''
+        if offx_or_name in self.memcfg:
+            return self.memcfg[offx_or_name]
+
+        elif isinstance(offx_or_name, int):
+            for mem in self.memcfg.values():
+                if mem.origin <= offx_or_name < mem.origin+mem.length:
+                    return mem
+            else:
+                return self.defaultmem
+
+        raise ValueError('Invalid argument type for indexing')
+
+    def _skip(self, regex):
+        matcher = re.compile(regex)
+        for l in self:
+            if matcher.match(l):
+                break
+
+    def __iter__(self):
+        while self._lines:
+            yield self._lines.pop(0)
+
+    def _parse(self):
+        self._skip('^Memory Configuration')
+
+        # Parse memory segmentation info
+        self._skip('^Name')
+        for l in self:
+            if not l:
+                break
+            name, origin, length, *attrs = l.split()
+            if not name.startswith('*'):
+                self.memcfg[name] = Memory(name, int(origin, 16), int(length, 16), attrs[0] if attrs else '')
+
+        # Parse section information
+        toplevel_m = re.compile('^(\.[a-zA-Z0-9_.]+)\s+(0x[0-9a-fA-F]+)\s+(0x[0-9a-fA-F]+)')
+        secondlevel_m = re.compile('^ (\.[a-zA-Z0-9_.]+)\s+(0x[0-9a-fA-F]+)\s+(0x[0-9a-fA-F]+)\s+(.*)$')
+        secondlevel_linebreak_m = re.compile('^ (\.[a-zA-Z0-9_.]+)\n')
+        filelike = re.compile('^(/?[^()]*\.[a-zA-Z0-9-_]+)(\(.*\))?')
+        linebreak_section = None
+        for l in self:
+            # Toplevel section
+            match = toplevel_m.match(l)
+            if match:
+                name, offx, length = match.groups()
+                offx, length = int(offx, 16), int(length, 16)
+                self[offx].add_toplevel(name, offx, length)
+
+            match = secondlevel_linebreak_m.match(l)
+            if match:
+                linebreak_section, = match.groups()
+                continue
+
+            if linebreak_section:
+                l = ' {} {}'.format(linebreak_section, l)
+                linebreak_section = None
+
+            # Second-level section
+            match = secondlevel_m.match(l)
+            if match:
+                name, offx, length, misc = match.groups()
+                match = filelike.match(misc)
+                if match:
+                    fn, obj = match.groups()
+                    obj = obj.strip('()') if obj else None
+                    offx, length = int(offx, 16), int(length, 16)
+                    self[offx].add_obj(name, offx, length, fn, obj)
+
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser(description='Parser GCC map file')
+    parser.add_argument('mapfile', type=argparse.FileType('r'), help='The GCC .map file to parse')
+    parser.add_argument('-m', '--memory', type=str, help='The memory segments to print, comma-separated')
+    args = parser.parse_args()
+    mf = MapFile(args.mapfile.read())
+    args.mapfile.close()
+
+    mems = args.memory.split(',') if args.memory else mf.memcfg.keys()
+
+    for name in mems:
+        mem = mf.memcfg[name]
+        print('Symbols by file for memory', name)
+        for tot, fn in reversed(sorted( (tot, fn) for fn, tot in mem.totals.items() )):
+            print('    {:>8} {}'.format(tot, fn))
+            for length, offx, sec, obj in reversed(sorted(( (length, offx, sec, obj) for sec, obj, offx, length in
+                mem.files[fn] ), key=lambda e: e[0] )):
+                name = sec.name if sec else None
+                print('       {:>8} {:>#08x} {}'.format(length, offx, obj))
+        #print('{:>16} 0x{:016x} 0x{:016x} ({:>24}) {}'.format(name, origin, length, length, attrs))
+
diff --git a/tools/presig_gen.py b/tools/presig_gen.py
new file mode 100644
index 0000000..c5dafe7
--- /dev/null
+++ b/tools/presig_gen.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+import textwrap
+import uuid
+import hmac
+import binascii
+import time
+from datetime import datetime
+
+LINKING_KEY_SIZE = 15
+PRESIG_VERSION = '000.001'
+DOMAINS = ['all', 'country', 'region', 'vendor', 'series']
+
+def format_hex(data, indent=4, wrap=True):
+    indent = ' '*indent
+    par = ', '.join(f'0x{b:02x}' for b in data)
+    par = textwrap.fill(par, width=120,
+        initial_indent=indent, subsequent_indent=indent,
+        replace_whitespace=False, drop_whitespace=False)
+    if wrap:
+        return f'{{\n{par}\n}}'
+    return par
+
+def domain_string(domain, value):
+    return f'smart reset domain string v{PRESIG_VERSION}: domain:{domain}={value}'
+
+def keygen_cmd(args):
+    if os.path.exists(args.keyfile) and not args.force:
+        print("Error: keyfile already exists. We won't overwrite it. Instead please remove it manually.",
+                file=sys.stderr)
+        return 1
+
+    root_key = os.urandom(LINKING_KEY_SIZE)
+
+    with open(args.keyfile, 'wb') as f:
+        f.write(binascii.hexlify(root_key))
+        f.write(b'\n')
+    return 0
+
+def gen_at_height(domain, value, height, key):
+    # nanananananana BLOCKCHAIN!
+
+    ds = domain_string(domain, value).encode('utf-8')
+
+    for height in range(height+1):
+        key = hmac.digest(key, ds, 'sha512')[:LINKING_KEY_SIZE]
+
+    return key
+
+def auth_cmd(args):
+    with open(args.keyfile, 'r') as f:
+        root_key = binascii.unhexlify(f.read().strip())
+
+    vals = [ (domain, getattr(args, domain)) for domain in DOMAINS if getattr(args, domain) is not None ]
+    if not vals:
+        vals = [('all', 'all')]
+    for domain, value in vals:
+        auth = gen_at_height(domain, value, args.height, root_key)
+        print(f'{domain}="{value}" @{args.height}: {binascii.hexlify(auth).decode()}')
+
+
+def prekey_cmd(args):
+    with open(args.keyfile, 'r') as f:
+        root_key = binascii.unhexlify(f.read().strip())
+
+    print('#include <stdint.h>')
+    print('#include <assert.h>')
+    print()
+    print('#include "crypto.h"')
+    print()
+
+    bundle_id = uuid.uuid4().bytes
+    print(f'/* bundle id {binascii.hexlify(bundle_id).decode()} */')
+    print(f'uint8_t presig_bundle_id[16] = {format_hex(bundle_id)};')
+    print()
+    print(f'/* generated on {datetime.now()} */')
+    print(f'uint64_t bundle_timestamp = {int(time.time())};')
+    print()
+    print(f'int presig_height = {args.max_height};')
+    print()
+
+    print('const char *presig_domain_strings[_TRIGGER_DOMAIN_COUNT] = {')
+    for domain in DOMAINS:
+        ds = domain_string(domain, getattr(args, domain))
+        assert '"' not in ds
+        print(f'    [TRIGGER_DOMAIN_{domain.upper()}] = "{ds}",')
+    print('};')
+    print()
+
+    print('uint8_t presig_keys[_TRIGGER_DOMAIN_COUNT][PRESIG_MSG_LEN] = {')
+    for domain in DOMAINS:
+        key = gen_at_height(domain, getattr(args, domain), args.max_height, root_key)
+        print(f'    [TRIGGER_DOMAIN_{domain.upper()}] = {{{format_hex(key, indent=0, wrap=False)}}},')
+    print('};')
+
+    print()
+    print('static inline void __hack_asserts_only(void) {')
+    print(f'    static_assert(_TRIGGER_DOMAIN_COUNT == {len(DOMAINS)});')
+    print(f'    static_assert(PRESIG_MSG_LEN == {LINKING_KEY_SIZE});')
+    print('}')
+    print()
+
+
+
+TEST_VENDOR = 'Darthenschmidt Cyberei und Verschleierungstechnik GmbH'
+TEST_SERIES = 'Frobnicator v0.23.7'
+TEST_REGION = 'Neuland'
+TEST_COUNTRY = 'Germany'
+
+if __name__ == '__main__':
+    import argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('keyfile', help='Key file to use')
+
+    subparsers = parser.add_subparsers(title='subcommands')
+    keygen_parser = subparsers.add_parser('keygen', help='Generate a new key')
+    keygen_parser.add_argument('-f', '--force', action='store_true', help='Force overwriting existing keyfile')
+    keygen_parser.set_defaults(func=keygen_cmd)
+
+    auth_parser = subparsers.add_parser('auth', help='Generate one-time authentication string')
+    auth_parser.add_argument('height', type=int, help='Authentication string height, counting from 0 (root key)')
+    auth_parser.set_defaults(func=auth_cmd)
+    auth_parser.add_argument('-a', '--all', action='store_const', const='all', help='Vendor name for vendor domain')
+    auth_parser.add_argument('-v', '--vendor', type=str, nargs='?', const=TEST_VENDOR, help='Vendor name for vendor domain')
+    auth_parser.add_argument('-s', '--series', type=str, nargs='?', const=TEST_SERIES, help='Series identifier for series domain')
+    auth_parser.add_argument('-r', '--region', type=str, nargs='?', const=TEST_REGION, help='Region name for region domain')
+    auth_parser.add_argument('-c', '--country', type=str, nargs='?', const=TEST_COUNTRY, help='Country name for country domain')
+
+    prekey_parser = subparsers.add_parser('prekey', help='Generate prekey data .C source code file')
+    prekey_parser.add_argument('-m', '--max-height', type=int, default=8, help='Height of generated prekey')
+    prekey_parser.add_argument('-v', '--vendor', type=str, default=TEST_VENDOR, help='Vendor name for vendor domain')
+    prekey_parser.add_argument('-s', '--series', type=str, default=TEST_SERIES, help='Series identifier for series domain')
+    prekey_parser.add_argument('-r', '--region', type=str, default=TEST_REGION, help='Region name for region domain')
+    prekey_parser.add_argument('-c', '--country', type=str, default=TEST_COUNTRY, help='Country name for country domain')
+    prekey_parser.set_defaults(func=prekey_cmd, all='all')
+
+    args = parser.parse_args()
+    sys.exit(args.func(args))
+
diff --git a/tools/reed_solomon.py b/tools/reed_solomon.py
new file mode 100644
index 0000000..c4ca6e4
--- /dev/null
+++ b/tools/reed_solomon.py
@@ -0,0 +1,91 @@
+import os, sys
+import ctypes as C
+import argparse
+import binascii
+import numpy as np
+import timeit
+import statistics
+
+lib = C.CDLL('rslib.so')
+
+lib.rslib_encode.argtypes = [C.c_int, C.c_size_t, C.POINTER(C.c_char), C.POINTER(C.c_char)]
+lib.rslib_decode.argtypes = [C.c_int, C.c_size_t, C.POINTER(C.c_char)]
+lib.rslib_gexp.argtypes = [C.c_int, C.c_int]
+lib.rslib_gexp.restype = C.c_int
+lib.rslib_decode.restype = C.c_int
+lib.rslib_npar.restype = C.c_size_t
+
+def npar():
+    return lib.rslib_npar()
+
+def encode(data: bytes, nbits=8):
+    out = C.create_string_buffer(len(data) + lib.rslib_npar())
+    lib.rslib_encode(nbits, len(data), data, out)
+    return out.raw
+
+def decode(data: bytes, nbits=8):
+    inout = C.create_string_buffer(data)
+    lib.rslib_decode(nbits, len(data), inout)
+    return inout.raw[:-lib.rslib_npar() - 1]
+
+def cmdline_func_test(args, print=lambda *args, **kwargs: None, benchmark=False):
+    st = np.random.RandomState(seed=args.seed)
+
+    lfsr = [lib.rslib_gexp(i, args.bits) for i in range(2**args.bits - 1)]
+    print('LFSR', len(set(lfsr)), lfsr)
+    assert all(0 < x < 2**args.bits for x in lfsr)
+    assert len(set(lfsr)) == 2**args.bits - 1
+
+    print('Seed', args.seed)
+    for i in range(args.repeat):
+        print(f'Run {i}')
+        test_data = bytes(st.randint(2**args.bits, size=args.message_length, dtype=np.uint8))
+        print('        Raw:', binascii.hexlify(test_data).decode())
+        encoded = encode(test_data, nbits=args.bits)
+        print('     Encoded:', binascii.hexlify(encoded).decode())
+
+        indices = st.permutation(len(encoded))
+        encoded = list(encoded)
+        for pos in indices[:args.errors]:
+            encoded[pos] = st.randint(2**args.bits)
+        encoded = bytes(encoded)
+        print('    Modified:', ''.join(f'\033[91m{b:02x}\033[0m' if pos in indices[:args.errors] else f'{b:02x}' for pos, b in enumerate(encoded)))
+
+        if benchmark:
+            rpt = 10000
+            delta = timeit.timeit('decode(encoded, nbits=args.bits)',
+                    globals={'args': args, 'decode': decode, 'encoded': encoded},
+                    number=rpt)/rpt
+            print(f'Decoding runtime: {delta*1e6:.3f}μs')
+        decoded = decode(encoded, nbits=args.bits)
+        print('     Decoded:', binascii.hexlify(decoded).decode())
+        print('       Delta:', binascii.hexlify(
+                bytes(x^y for x, y in zip(test_data, decoded))
+            ).decode().replace('0', '.'))
+        assert test_data == decoded
+
+def cmdline_func_encode(args, **kwargs):
+    data = np.frombuffer(binascii.unhexlify(args.hex_str), dtype=np.uint8)
+    # Map 8 bit input to 6 bit symbol string
+    data = np.packbits(np.pad(np.unpackbits(data).reshape((-1, 6)), ((0,0),(2, 0))).flatten())
+    encoded = encode(data.tobytes(), nbits=args.bits)
+    print('symbol array:', ', '.join(f'0x{x:02x}' for x in encoded))
+    print('hex string:', binascii.hexlify(encoded).decode())
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    cmd_parser = parser.add_subparsers(required=True)
+    test_parser = cmd_parser.add_parser('test', help='Test reed-solomon implementation')
+    test_parser.add_argument('-m', '--message-length', type=int, default=6, help='Test message (plaintext) length in bytes')
+    test_parser.add_argument('-e', '--errors', type=int, default=2, help='Number of byte errors to insert into simulation')
+    test_parser.add_argument('-r', '--repeat', type=int, default=1000, help='Repeat experiment -r times')
+    test_parser.add_argument('-b', '--bits', type=int, default=8, help='Symbol bit size')
+    test_parser.add_argument('-s', '--seed', type=int, default=0, help='Random seed')
+    test_parser.set_defaults(func=cmdline_func_test)
+    enc_parser = cmd_parser.add_parser('encode', help='RS-Encode given hex string')
+    enc_parser.set_defaults(func=cmdline_func_encode)
+    enc_parser.add_argument('-b', '--bits', type=int, default=8, help='Symbol bit size')
+    enc_parser.add_argument('hex_str', type=str, help='Input data as hex string')
+    args = parser.parse_args()
+    args.func(args)
+