betaflight/src/drv_system.c

#include "board.h"

typedef struct gpio_config_t
{
    GPIO_TypeDef *gpio;
    uint16_t pin;
    GPIOMode_TypeDef mode;
} gpio_config_t;

// cycles per microsecond
static volatile uint32_t usTicks = 0;
// current uptime for 1kHz systick timer. will rollover after 49 days. hopefully we won't care.
static volatile uint32_t sysTickUptime = 0;

static void cycleCounterInit(void)
{
    RCC_ClocksTypeDef clocks;
    RCC_GetClocksFreq(&clocks);
    usTicks = clocks.SYSCLK_Frequency / 1000000;
}

// SysTick
void SysTick_Handler(void)
{
    sysTickUptime++;
}

// Return system uptime in microseconds (rollover in 70minutes)
uint32_t micros(void)
{
    register uint32_t ms, cycle_cnt;
    do {
        ms = sysTickUptime;
        cycle_cnt = SysTick->VAL;
    } while (ms != sysTickUptime);
    return (ms * 1000) + (usTicks * 1000 - cycle_cnt) / usTicks;
}

// Return system uptime in milliseconds (rollover in 49 days)
uint32_t millis(void)
{
    return sysTickUptime;
}

void systemInit(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    uint32_t i;

    gpio_config_t gpio_cfg[] = {
        { LED0_GPIO, LED0_PIN, GPIO_Mode_Out_PP },
        { LED1_GPIO, LED1_PIN, GPIO_Mode_Out_PP },
#ifdef BUZZER
        { BEEP_GPIO, BEEP_PIN, GPIO_Mode_Out_OD },
#endif
    };
    uint8_t gpio_count = sizeof(gpio_cfg) / sizeof(gpio_cfg[0]);

    // This is needed because some shit inside Keil startup fucks with SystemCoreClock, setting it back to 72MHz even on HSI.
    SystemCoreClockUpdate();

    // Turn on clocks for stuff we use
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2 | RCC_APB1Periph_TIM3 | RCC_APB1Periph_TIM4 | RCC_APB1Periph_I2C2, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC | RCC_APB2Periph_TIM1 | RCC_APB2Periph_ADC1 | RCC_APB2Periph_USART1, ENABLE);
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
    RCC_ClearFlag();

    // Make all GPIO in by default to save power and reduce noise
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    GPIO_Init(GPIOB, &GPIO_InitStructure);
    GPIO_Init(GPIOC, &GPIO_InitStructure);

    // Turn off JTAG port 'cause we're using the GPIO for leds
    GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable, ENABLE);

    // Configure gpio
    for (i = 0; i < gpio_count; i++) {
        GPIO_InitStructure.GPIO_Pin = gpio_cfg[i].pin;
        GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
        GPIO_InitStructure.GPIO_Mode = gpio_cfg[i].mode;
        GPIO_Init(gpio_cfg[i].gpio, &GPIO_InitStructure);
    }

    LED0_OFF;
    LED1_OFF;
    BEEP_OFF;

    // Init cycle counter
    cycleCounterInit();

    // SysTick
    SysTick_Config(SystemCoreClock / 1000);

    // Configure the rest of the stuff
#ifndef FY90Q
    i2cInit(I2C2);
#endif

    // sleep for 100ms
    delay(100);
}

#if 1
void delayMicroseconds(uint32_t us)
{
    uint32_t now = micros();
    while (micros() - now < us);
}
#else
void delayMicroseconds(uint32_t us)
{
    uint32_t elapsed = 0;
    uint32_t lastCount = SysTick->VAL;

    for (;;) {
        register uint32_t current_count = SysTick->VAL;
        uint32_t elapsed_us;

        // measure the time elapsed since the last time we checked
        elapsed += current_count - lastCount;
        lastCount = current_count;

        // convert to microseconds
        elapsed_us = elapsed / usTicks;
        if (elapsed_us >= us)
            break;

        // reduce the delay by the elapsed time
        us -= elapsed_us;

        // keep fractional microseconds for the next iteration
        elapsed %= usTicks;
    }
}
#endif

void delay(uint32_t ms)
{
    while (ms--)
        delayMicroseconds(1000);
}

void failureMode(uint8_t mode)
{
    LED1_ON;
    LED0_OFF;
    while (1) {
        LED1_TOGGLE;
        LED0_TOGGLE;
        delay(475 * mode - 2);
        BEEP_ON
        delay(25);
        BEEP_OFF;
    }
}

#define AIRCR_VECTKEY_MASK    ((uint32_t)0x05FA0000)

void systemReset(bool toBootloader)
{
    if (toBootloader) {
        // 1FFFF000 -> 20000200 -> SP
        // 1FFFF004 -> 1FFFF021 -> PC
        *((uint32_t *)0x20004FF0) = 0xDEADBEEF; // 20KB STM32F103
    }

    // Generate system reset
    SCB->AIRCR = AIRCR_VECTKEY_MASK | (uint32_t)0x04;
}