/* Megumin LED display firmware
* Copyright (C) 2018 Sebastian Götte <code@jaseg.net>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "global.h"
#include "adc.h"
#include "serial.h"
volatile unsigned int sys_time_seconds = 0;
volatile union leds leds;
volatile int32_t gps_1pps_period_sysclk = -1;
int main(void) {
/* Get GPIOA and SPI1 up to flash status LEDs */
RCC->AHBENR |= RCC_AHBENR_GPIOAEN;
RCC->APB2ENR |= RCC_APB2ENR_SPI1EN;
GPIOA->MODER |=
(3<<GPIO_MODER_MODER2_Pos) /* PA2 - LINE_MEAS */
| (1<<GPIO_MODER_MODER3_Pos) /* PA3 - LED_STB */
| (1<<GPIO_MODER_MODER4_Pos) /* PA4 - SD_CS */
| (2<<GPIO_MODER_MODER5_Pos) /* PA5 - SCK */
| (2<<GPIO_MODER_MODER6_Pos) /* PA6 - MISO */
| (2<<GPIO_MODER_MODER7_Pos) /* PA7 - MOSI */
| (2<<GPIO_MODER_MODER9_Pos) /* PA9 - HOST_RX */
| (2<<GPIO_MODER_MODER10_Pos);/* PA10 - HOST_TX */
/* Set shift register IO GPIO output speed */
GPIOA->OSPEEDR |=
(2<<GPIO_OSPEEDR_OSPEEDR3_Pos) /* LED_STB */
| (2<<GPIO_OSPEEDR_OSPEEDR4_Pos) /* SD_CS */
| (2<<GPIO_OSPEEDR_OSPEEDR5_Pos) /* SCK */
| (2<<GPIO_OSPEEDR_OSPEEDR7_Pos) /* MOSI */
| (2<<GPIO_OSPEEDR_OSPEEDR9_Pos); /* HOST_RX */
GPIOA->AFR[0] = (0<<GPIO_AFRL_AFRL5_Pos) | (0<<GPIO_AFRL_AFRL6_Pos) | (0<<GPIO_AFRL_AFRL7_Pos);
GPIOA->AFR[1] = (1<<8) | (1<<4);
SPI1->CR1 =
SPI_CR1_SSM
| SPI_CR1_SSI
| SPI_CR1_CPOL
| SPI_CR1_CPHA
| (4<<SPI_CR1_BR_Pos) /* /32 ~1.5MHz */
| SPI_CR1_MSTR;
SPI1->CR2 = (7<<SPI_CR2_DS_Pos);
SPI1->CR1 |= SPI_CR1_SPE;
*((volatile uint8_t*)&(SPI1->DR)) = 0xff;
/* Wait for OCXO to settle */
for (int i=0; i<1000000; i++)
;
/* Switch clock to PLL based on OCXO input */
RCC->CR |= RCC_CR_HSEBYP;
RCC->CR |= RCC_CR_HSEON;
RCC->CFGR &= ~RCC_CFGR_PLLMUL_Msk & ~RCC_CFGR_SW_Msk & ~RCC_CFGR_PPRE_Msk & ~RCC_CFGR_HPRE_Msk;
/* PLL config: 19.44MHz /2 x5 -> 48.6MHz */
RCC->CFGR |= ((5-2)<<RCC_CFGR_PLLMUL_Pos) | RCC_CFGR_PLLSRC_HSE_PREDIV;
RCC->CFGR2 = ((2-1)<<RCC_CFGR2_PREDIV_Pos);
RCC->CR |= RCC_CR_PLLON;
while (!(RCC->CR&RCC_CR_PLLRDY));
RCC->CFGR |= (2<<RCC_CFGR_SW_Pos);
SystemCoreClockUpdate();
/* Start systick */
SysTick_Config(SystemCoreClock/10); /* 100ms interval */
NVIC_EnableIRQ(SysTick_IRQn);
NVIC_SetPriority(SysTick_IRQn, 3<<5);
/* Turn on rest of periphery */
RCC->AHBENR |= RCC_AHBENR_DMAEN | RCC_AHBENR_GPIOBEN | RCC_AHBENR_FLITFEN | RCC_AHBENR_CRCEN;
RCC->APB2ENR |= RCC_APB2ENR_SYSCFGEN | RCC_APB2ENR_ADCEN | RCC_APB2ENR_DBGMCUEN |\
RCC_APB2ENR_TIM1EN | RCC_APB2ENR_TIM16EN | RCC_APB2ENR_USART1EN;
RCC->APB1ENR |= RCC_APB1ENR_TIM3EN | RCC_APB1ENR_TIM14EN;
GPIOB->MODER |=
(2<<GPIO_MODER_MODER1_Pos); /* PB0 - GPS 1pps input */
GPIOB->AFR[0] = (0<<GPIO_AFRL_AFRL1_Pos);
GPIOB->PUPDR = 2<<GPIO_PUPDR_PUPDR1_Pos;
/* Configure TIM16 for LED update via SPI */
TIM16->CR2 = 0;
TIM16->DIER = TIM_DIER_UIE | TIM_DIER_CC1IE;
TIM16->CCMR1 = 0;
TIM16->CCR1 = 32;
TIM16->PSC = 48-1; /* 1us */
TIM16->ARR = 1000-1; /* 1ms */
TIM16->CR1 = TIM_CR1_CEN;
NVIC_EnableIRQ(TIM16_IRQn);
/* Configure TIM14 for GPS 1pps input capture */
TIM14->CCMR1 = (1<<TIM_CCMR1_CC1S_Pos) | (3<<TIM_CCMR1_IC1F_Pos);
TIM14->CCER = TIM_CCER_CC1E;
TIM14->PSC = 1;
TIM14->ARR = 0xffff;
TIM14->DIER = TIM_DIER_CC1IE | TIM_DIER_UIE;
TIM14->EGR = TIM_EGR_UG;
TIM14->CR1 |= TIM_CR1_CEN;
NVIC_EnableIRQ(TIM14_IRQn);
adc_init(1000000);
adc_timer_init(243, 200); /* 19.44 MHz / 243 -> 200 kHz; /200 -> 1 kHz */
usart_dma_init();
while (42) {
/* Do nothing and let the interrupts do all the work. */
}
}
void tim14_sr_cc1of(void) {} /* gdb hook */
void TIM14_IRQHandler(void) {
static uint32_t gps_1pps_period = 0;
static uint32_t update_inc = 0;
static bool in_sync = false;
uint32_t sr = TIM14->SR;
if (sr & TIM_SR_CC1OF) {
TIM14->SR &= ~(TIM_SR_CC1IF | TIM_SR_CC1OF);
tim14_sr_cc1of();
}
if (sr & TIM_SR_UIF) {
TIM14->SR &= ~TIM_SR_UIF;
if (in_sync) {
gps_1pps_period += update_inc;
if (gps_1pps_period > 30000000) { /* Signal out of range */
in_sync = false;
gps_1pps_period_sysclk = -1;
gps_1pps_period = (uint32_t)-1;
}
}
update_inc = 0x10000;
}
if (sr & TIM_SR_CC1IF) { /* CC1 event (GPS 1pps input) */
/* Don't reset update event: If update event arrives while CC1 event is being processed leave UIF set to process
* update event immediately after return from ISR. */
uint16_t ccr = TIM14->CCR1;
if (in_sync) {
uint32_t new_period = gps_1pps_period + ccr;
if (new_period < 20000000 || new_period > 30000000) { /* Signal out of range */
in_sync = false;
gps_1pps_period_sysclk = -1;
gps_1pps_period = (uint32_t)-1;
} else {
if ((sr & TIM_SR_UIF) /* we processed an update event in this ISR */
&& (ccr > 0xc000) /* and the capture happened late in the cycle */
) {
gps_1pps_period_sysclk = new_period - 0x10000;
update_inc = 0x10000;
gps_1pps_period = 0x10000 - ccr;
} else {
gps_1pps_period_sysclk = new_period;
update_inc = 0x10000 - ccr; /* remaining cycles in this period */
gps_1pps_period = 0;
}
leds.pps = 200; /* ms */
}
} else {
gps_1pps_period = 0;
update_inc = 0x10000 - ccr; /* remaining cycles in this period */
in_sync = true;
}
}
}
void TIM16_IRQHandler(void) {
static int leds_update_counter = 0;
if (TIM16->SR & TIM_SR_UIF) {
TIM16->SR &= ~TIM_SR_UIF;
uint8_t bits = 0, mask = 1;
for (int i=0; i<8; i++) {
if (leds.arr[i]) {
leds.arr[i]--;
bits |= mask;
}
mask <<= 1;
}
if (leds_update_counter++ == 10) {
leds_update_counter = 0;
/* Workaround for SPI hardware bug: Even if configured to 8-bit mode, the SPI will do a 16-bit transfer if the
* data register is accessed through a 16-bit write. Unfortunately, the STMCube register defs define DR as an
* uint16_t, so we have to do some magic here to force an 8-bit write. */
*((volatile uint8_t*)&(SPI1->DR)) = bits;
GPIOA->BRR = 1<<3;
}
} else {
TIM16->SR &= ~TIM_SR_CC1IF;
GPIOA->BSRR = 1<<3;
}
}
void NMI_Handler(void) {
asm volatile ("bkpt");
}
void HardFault_Handler(void) __attribute__((naked));
void HardFault_Handler() {
asm volatile ("bkpt");
}
void SVC_Handler(void) {
asm volatile ("bkpt");
}
void PendSV_Handler(void) {
asm volatile ("bkpt");
}
void SysTick_Handler(void) {
static int n = 0;
if (n++ == 10) {
n = 0;
sys_time_seconds++;
if (gps_1pps_period_sysclk < 0)
leds.pps = 200; /* ms */
}
}