Working rainbow code

2 files changed, 122 insertions, 137 deletions

diff --git a/olsndot/firmware/Makefile b/olsndot/firmware/Makefile
index cf338eb..625865d 100644
--- a/olsndot/firmware/Makefile
+++ b/olsndot/firmware/Makefile
@@ -10,13 +10,13 @@ SIZE    := arm-none-eabi-size
 
 CFLAGS  = -Wall -g -std=gnu11 -Os  
 CFLAGS += -mlittle-endian -mcpu=cortex-m0 -march=armv6-m -mthumb
-CFLAGS += -ffunction-sections -fdata-sections
-CFLAGS += -Wl,--gc-sections -Wl,-Map=main.map
+CFLAGS += -ffunction-sections -fdata-sections -Wl,--gc-sections 
+CFLAGS += -Wl,-Map=main.map
 
 # Technically we're using an STM32F030F4, but apart from the TSSOP20 package that one is largely identical to the
 # STM32F030*6 and there is no separate device header provided for it, so we're faking a *6 device here. This is
 # even documented in stm32f0xx.h. Thanks ST!
-CFLAGS += -DSTM32F030x6
+CFLAGS += -DSTM32F030x6 -DHSE_VALUE=16000000
 
 CFLAGS += -Tstm32_flash.ld
 CFLAGS += -I$(CMSIS_DEV_PATH)/Include -I$(CMSIS_PATH)/Include -I$(HAL_PATH)/Inc -Iconfig
@@ -28,6 +28,9 @@ CFLAGS += -L$(CMSIS_PATH)/Lib/GCC -larm_cortexM0l_math
 
 all: main.elf
 
+cmsis_exports.c: $(CMSIS_DEV_PATH)/Include/stm32f030x6.h $(CMSIS_PATH)/Include/core_cm0.h
+	python3 gen_cmsis_exports.py $^ > $@
+
 main.elf: main.c startup_stm32f030x6.s system_stm32f0xx.c $(HAL_PATH)/Src/stm32f0xx_ll_utils.c
 	$(CC) $(CFLAGS) -o $@ $^
 	$(OBJCOPY) -O ihex $@ $(@:.elf=.hex)
diff --git a/olsndot/firmware/main.c b/olsndot/firmware/main.c
index e4b3935..1b3e054 100644
--- a/olsndot/firmware/main.c
+++ b/olsndot/firmware/main.c
@@ -3,26 +3,72 @@
 #include <stdint.h>
 #include <system_stm32f0xx.h>
 #include <stm32f0xx_ll_utils.h>
+#include <math.h>
 /* 
  * Part number: STM32F030F4C6
  */
 
 #define NBITS 12
 void do_transpose(void);
-uint32_t brightness[8];
-volatile uint8_t brightness_by_bit[NBITS];
+uint32_t brightness[32];
+volatile uint32_t brightness_by_bit[NBITS];
+
+void hsv_set(int idx, int hue, int white) {
+    int i = hue>>NBITS;
+    int j = hue & (~(-1<<NBITS));
+    int r=0, g=0, b=0;
+    switch (i) {
+        case 0:
+        r = (1<<NBITS)-1;
+        g = 0;
+        b = j;
+        break;
+        case 1:
+        r = (1<<NBITS)-1-j;
+        g = 0;
+        b = (1<<NBITS)-1;
+        break;
+        case 2:
+        r = 0;
+        g = j;
+        b = (1<<NBITS)-1;
+        break;
+        case 3:
+        r = 0;
+        g = (1<<NBITS)-1;
+        b = (1<<NBITS)-1-j;
+        break;
+        case 4:
+        r = j;
+        g = (1<<NBITS)-1;
+        b = 0;
+        break;
+        case 5:
+        r = (1<<NBITS)-1;
+        g = (1<<NBITS)-1-j;
+        b = 0;
+        break;
+    }
+    brightness[idx*4 + 0] = white;
+    brightness[idx*4 + 1] = r;
+    brightness[idx*4 + 2] = g;
+    brightness[idx*4 + 3] = b;
+}
 
+int hue;
 int main(void) {
     RCC->CR |= RCC_CR_HSEON;
     while (!(RCC->CR&RCC_CR_HSERDY));
-    RCC->CFGR &= ~RCC_CFGR_PLLMUL_Msk & ~RCC_CFGR_SW_Msk;
-    RCC->CFGR |= (2<<RCC_CFGR_PLLMUL_Pos) | RCC_CFGR_PLLSRC; /* PLL x4 */
+    RCC->CFGR &= ~RCC_CFGR_PLLMUL_Msk & ~RCC_CFGR_SW_Msk & ~RCC_CFGR_PPRE_Msk & ~RCC_CFGR_HPRE_Msk;
+    RCC->CFGR |= (2<<RCC_CFGR_PLLMUL_Pos) | RCC_CFGR_PLLSRC_HSE_PREDIV; /* PLL x4 -> 50.0MHz */
+    RCC->CFGR2 &= ~RCC_CFGR2_PREDIV_Msk;
+    RCC->CFGR2 |= RCC_CFGR2_PREDIV_DIV2; /* prediv :2 -> 12.5MHz */
     RCC->CR |= RCC_CR_PLLON;
     while (!(RCC->CR&RCC_CR_PLLRDY));
     RCC->CFGR |= (2<<RCC_CFGR_SW_Pos);
     SystemCoreClockUpdate();
 
-    LL_Init1msTick(SystemCoreClock);
+
 
     RCC->AHBENR  |= RCC_AHBENR_GPIOAEN | RCC_AHBENR_GPIOBEN;
     RCC->APB2ENR |= RCC_APB2ENR_SPI1EN | RCC_APB2ENR_TIM1EN | RCC_APB2ENR_USART1EN | RCC_APB2ENR_ADCEN;
@@ -32,26 +78,26 @@ int main(void) {
         | (1<<GPIO_MODER_MODER1_Pos)  /* PA1  - RS485 TX enable */
         | (2<<GPIO_MODER_MODER2_Pos)  /* PA2  - RS485 TX */
         | (2<<GPIO_MODER_MODER3_Pos)  /* PA3  - RS485 RX */
-        | (1<<GPIO_MODER_MODER4_Pos)  /* PA4  - LED1 open-drain output */
+        /* PA4 reserved because */
         | (2<<GPIO_MODER_MODER5_Pos)  /* PA5  - Shift register clk/SCLK */
         | (1<<GPIO_MODER_MODER6_Pos)  /* PA6  - LED2 open-drain output */
         | (2<<GPIO_MODER_MODER7_Pos)  /* PA7  - Shift register data/MOSI */
-        | (2<<GPIO_MODER_MODER9_Pos)  /* PA9  - Shift register clear (TIM1_CH2) */
+        | (2<<GPIO_MODER_MODER9_Pos)  /* FIXME PA9  - Shift register clear (TIM1_CH2) */
         | (2<<GPIO_MODER_MODER10_Pos);/* PA10 - Shift register strobe (TIM1_CH3) */
     GPIOB->MODER |=
-          (1<<GPIO_MODER_MODER1_Pos); /* PB1  - Current measurement range selection */
+          (2<<GPIO_MODER_MODER1_Pos); /* PB1  - Shift register clear (TIM1_CH3N) */
 
 
-    GPIOA->OTYPER |= GPIO_OTYPER_OT_6 | GPIO_OTYPER_OT_4; /* LED outputs -> open drain */
+    GPIOA->OTYPER |= GPIO_OTYPER_OT_6; /* LED outputs -> open drain */
 
     /* Set shift register IO GPIO output speed */
     GPIOA->OSPEEDR |=
-          (3<<GPIO_OSPEEDR_OSPEEDR4_Pos)  /* LED1   */
-        | (3<<GPIO_OSPEEDR_OSPEEDR5_Pos)  /* SCLK   */
-        | (3<<GPIO_OSPEEDR_OSPEEDR6_Pos)  /* LED2   */
+          (3<<GPIO_OSPEEDR_OSPEEDR5_Pos)  /* SCLK   */
+        | (3<<GPIO_OSPEEDR_OSPEEDR6_Pos)  /* LED1   */
         | (3<<GPIO_OSPEEDR_OSPEEDR7_Pos)  /* MOSI   */
-        | (3<<GPIO_OSPEEDR_OSPEEDR9_Pos)  /* Clear */
         | (3<<GPIO_OSPEEDR_OSPEEDR10_Pos);/* Strobe */
+    GPIOB->OSPEEDR |=
+          (3<<GPIO_OSPEEDR_OSPEEDR1_Pos); /* Clear  */
 
     GPIOA->AFR[0] |=
           (1<<GPIO_AFRL_AFRL2_Pos)   /* USART1_TX */
@@ -59,38 +105,27 @@ int main(void) {
         | (0<<GPIO_AFRL_AFRL5_Pos)   /* SPI1_SCK  */
         | (0<<GPIO_AFRL_AFRL7_Pos);  /* SPI1_MOSI */
     GPIOA->AFR[1] |=
-          (2<<GPIO_AFRH_AFRH1_Pos)   /* TIM1_CH2 */
-        | (2<<GPIO_AFRH_AFRH2_Pos);  /* TIM1_CH3  */
+          (2<<GPIO_AFRH_AFRH2_Pos);  /* TIM1_CH3  */
+    GPIOB->AFR[0] |=
+          (2<<GPIO_AFRL_AFRL1_Pos);  /* TIM1_CH3N */
     
-    GPIOB->BSRR = GPIO_BSRR_BR_1; /* clear output is active low */
-
     /* Configure SPI controller */
     /* CPOL=0, CPHA=0, prescaler=8 -> 1MBd */
-//    SPI1->CR1 = SPI_CR1_BIDIMODE | SPI_CR1_BIDIOE | SPI_CR1_SSM | SPI_CR1_SSI | SPI_CR1_SPE | (2<<SPI_CR1_BR_Pos) | SPI_CR1_MSTR;
     SPI1->CR1 = SPI_CR1_BIDIMODE | SPI_CR1_BIDIOE | SPI_CR1_SSM | SPI_CR1_SSI | SPI_CR1_SPE | (0<<SPI_CR1_BR_Pos) | SPI_CR1_MSTR;
-    SPI1->CR2 = (7<<SPI_CR2_DS_Pos);
+    SPI1->CR2 = (0xf<<SPI_CR2_DS_Pos);
     /* Configure TIM1 for display strobe generation */
     /* Configure UART for RS485 comm */
     /* 8N1, 115200Bd */
-//    TIM1->CR1 = TIM_CR1_OPM | TIM_CR1_URS;
-//    TIM1->CR1 = TIM_CR1_ARPE | TIM_CR1_URS;
-    TIM1->CR1 = TIM_CR1_ARPE | TIM_CR1_OPM; // | TIM_CR1_URS;
-    TIM1->CR2 = 0; //TIM_CR2_CCPC;
-    TIM1->SMCR = 0;
-    TIM1->DIER = 0;
+    TIM1->CR1 = TIM_CR1_ARPE; // | TIM_CR1_OPM; // | TIM_CR1_URS;
 
     TIM1->PSC = 1; // debug
     /* CH2 - clear/!MR, CH3 - strobe/STCP */
-    TIM1->CCR2 = 1;
-    TIM1->RCR = 0;
-    TIM1->CCMR1 = (6<<TIM_CCMR1_OC2M_Pos); // | TIM_CCMR1_OC2PE;
     TIM1->CCMR2 = (6<<TIM_CCMR2_OC3M_Pos); // | TIM_CCMR2_OC3PE;
-    TIM1->CCER |= TIM_CCER_CC2E | TIM_CCER_CC2NE | TIM_CCER_CC2P | TIM_CCER_CC3E;
-//    TIM1->CCMR1 = (6<<TIM_CCMR1_OC2M_Pos) | TIM_CCMR1_OC2PE;
-//    TIM1->CCMR2 = (6<<TIM_CCMR2_OC3M_Pos) | TIM_CCMR2_OC3PE;
-//    TIM1->CCER = TIM_CCER_CC2E | TIM_CCER_CC3E;
-//    TIM1->BDTR = TIM_BDTR_MOE;
+    TIM1->CCER |= TIM_CCER_CC3E | TIM_CCER_CC3NE | TIM_CCER_CC3P | TIM_CCER_CC3NP;
+    TIM1->BDTR = TIM_BDTR_MOE | (8<<TIM_BDTR_DTG_Pos); /* 1us dead time */
     TIM1->DIER = TIM_DIER_UIE;
+    TIM1->ARR = 1;
+    TIM1->CR1 |= TIM_CR1_CEN;
 
     NVIC_EnableIRQ(TIM1_BRK_UP_TRG_COM_IRQn);
     NVIC_SetPriority(TIM1_BRK_UP_TRG_COM_IRQn, 2);
@@ -98,88 +133,35 @@ int main(void) {
     TIM1->EGR |= TIM_EGR_UG;
 
     while (42) {
-        /*
-        for (uint8_t i=0; i<8; i++) {
-            brightness[1] = brightness[5] = i;
-            brightness[2] = brightness[6] = 0;
-            brightness[3] = brightness[7] = 0;
-            do_transpose();
-            LL_mDelay(500);
-        }
-        for (uint8_t i=0; i<8; i++) {
-            brightness[1] = brightness[5] = 0;
-            brightness[2] = brightness[6] = i;
-            brightness[3] = brightness[7] = 0;
-            do_transpose();
-            LL_mDelay(500);
-        }
-        for (uint8_t i=0; i<8; i++) {
-            brightness[1] = brightness[5] = 0;
-            brightness[2] = brightness[6] = 0;
-            brightness[3] = brightness[7] = i;
-            do_transpose();
-            LL_mDelay(500);
-        }
-        for (uint8_t i=0; i<8; i++) {
-            brightness[1] = brightness[5] = i;
-            brightness[2] = brightness[6] = i;
-            brightness[3] = brightness[7] = i;
+#define HUE_MAX ((1<<NBITS)*6)
+#define HUE_OFFX 0.15F /* 0-1 */
+#define HUE_AMPLITUDE 0.05F /* 0-1 */
+#define CHANNEL_SPACING 1.5F /* in radians */
+#define WHITE 0.2F /* 0-1 */
+        for (float v=0; v<8*M_PI; v += 0.01F) {
+            GPIOA->ODR ^= GPIO_ODR_6;
+            /* generate hsv fade */
+            for (int ch=0; ch<8; ch++) {
+                hue = HUE_MAX * (HUE_OFFX + HUE_AMPLITUDE*sinf(v + ch*CHANNEL_SPACING));
+                hue %= HUE_MAX;
+                hsv_set(ch, hue, WHITE*(1<<NBITS));
+            }
             do_transpose();
-            LL_mDelay(500);
-        }
-    }
-    {
-    */
-        for (uint32_t i=0; i<6; i++) {
-            for (uint32_t j=0; j<(1<<NBITS); j++) {
-                GPIOA->ODR ^= GPIO_ODR_6;
-                switch (i) {
-                    case 0:
-                    brightness[1] = brightness[5] = (1<<NBITS)-1;
-                    brightness[2] = brightness[6] = 0;
-                    brightness[3] = brightness[7] = j;
-                    break;
-                    case 1:
-                    brightness[1] = brightness[5] = (1<<NBITS)-1-j;
-                    brightness[2] = brightness[6] = 0;
-                    brightness[3] = brightness[7] = (1<<NBITS)-1;
-                    break;
-                    case 2:
-                    brightness[1] = brightness[5] = 0;
-                    brightness[2] = brightness[6] = j;
-                    brightness[3] = brightness[7] = (1<<NBITS)-1;
-                    break;
-                    case 3:
-                    brightness[1] = brightness[5] = 0;
-                    brightness[2] = brightness[6] = (1<<NBITS)-1;
-                    brightness[3] = brightness[7] = (1<<NBITS)-1-j;
-                    break;
-                    case 4:
-                    brightness[1] = brightness[5] = j;
-                    brightness[2] = brightness[6] = (1<<NBITS)-1;
-                    brightness[3] = brightness[7] = 0;
-                    break;
-                    case 5:
-                    brightness[1] = brightness[5] = (1<<NBITS)-1;
-                    brightness[2] = brightness[6] = (1<<NBITS)-1-j;
-                    brightness[3] = brightness[7] = 0;
-                    break;
-                }
-                do_transpose();
-                LL_mDelay(1);
+            for (int k=0; k<10000; k++) {
+                asm volatile("nop");
             }
         }
     }
 }
 
-uint32_t brightness[8] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
-volatile uint8_t brightness_by_bit[NBITS] = { 0 };
+uint32_t brightness[32] = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+volatile uint32_t brightness_by_bit[NBITS] = { 0 };
 
 void do_transpose(void) {
     for (uint32_t i=0; i<NBITS; i++) {
-        uint8_t bv = 0;
+        uint32_t bv = 0;
         uint32_t mask = 1<<i;
-        for (uint32_t j=0; j<8; j++) {
+        for (uint32_t j=0; j<32; j++) {
             if (brightness[j] & mask)
             bv |= 1<<j;
         }
@@ -187,44 +169,38 @@ void do_transpose(void) {
     }
 }
 
-/*
- * 460ns
- * 720ns
- */
-
-/*
- * 1.00us
- * 1.64us
- * 2.84us
- * 5.36us
- * 10.4us
- * 20.4us
- * 40.4us
- * 80.8us
- */
 void TIM1_BRK_UP_TRG_COM_IRQHandler(void) {
+    /* The index of the currently active bit. On entry of this function, this is the bit index of the upcoming period.
+     * On exit it is the index of the *next* period. */
     static uint32_t idx = 0;
+
+    /* Access bits offset by one as we are setting the *next* period based on idx below. */
+    uint32_t val = brightness_by_bit[idx];
+
     idx++;
     if (idx >= NBITS)
         idx = 0;
 
-    GPIOA->ODR ^= GPIO_ODR_4;
-    TIM1->CCMR1 = (4<<TIM_CCMR1_OC2M_Pos); // | TIM_CCMR1_OC2PE;
+    GPIOA->ODR ^= GPIO_ODR_6; /* LED1 */
 
-    SPI1->DR = brightness_by_bit[idx]<<8;
+    /* Shift out the current period's data. The shift register clear and strobe lines are handled by the timers
+     * capture/compare channel 3 complementary outputs. The dead-time generator is used to sequence the clear and strobe
+     * edges one after another. Since there may be small variations in IRQ service latency it is critical to allow for
+     * some leeway between the end of this data transmission and strobe and clear. */
+    SPI1->DR = (val&0xffff);
+    while (SPI1->SR & SPI_SR_BSY);
+    SPI1->DR = (val>>16);
     while (SPI1->SR & SPI_SR_BSY);
 
-    const uint32_t period_base = 4; /* 1us */
-    const uint32_t period = period_base<<idx;
-//    TIM1->BDTR  = TIM_BDTR_MOE | (16<<TIM_BDTR_DTG_Pos);
-    TIM1->BDTR = TIM_BDTR_MOE | (0<<TIM_BDTR_DTG_Pos);
-    TIM1->CCR3 = period-1;
-    TIM1->CNT = period-1;
-    TIM1->ARR = period;
-    TIM1->CCMR1 = (6<<TIM_CCMR1_OC2M_Pos); // | TIM_CCMR1_OC2PE;
-    TIM1->EGR |= TIM_EGR_UG;
-    TIM1->ARR = 2;
-    TIM1->CR1 |= TIM_CR1_CEN;
+    /* Set up everything for the *next* period. The timer is set to count from 0 to ARR. ARR and CCR3 are pre-loaded, so
+     * the values written above will only be latched on timer overrun at the end of this period. This is a little
+     * complicated, but doing it this way has the advantage of keeping both duty cycle and frame rate precisely
+     * constant. */
+    const int period_base = 4; /* 1us */
+    const int period = (period_base<<idx) + 4 /* 1us dead time */;
+    const int timer_cycles_for_spi_transmissions = 128;
+    TIM1->ARR = period + timer_cycles_for_spi_transmissions;
+    TIM1->CCR3 = timer_cycles_for_spi_transmissions;
     TIM1->SR &= ~TIM_SR_UIF_Msk;
 }
 
@@ -245,3 +221,9 @@ void PendSV_Handler(void) {
 void SysTick_Handler(void) {
 }
 
+/* FIXME */
+void _exit(void) {}
+void *__bss_start__;
+void *__bss_end__;
+
+int __errno;