atbetaflight/src/main/drivers/system.c

/*
 * This file is part of Cleanflight.
 *
 * Cleanflight 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.
 *
 * Cleanflight 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 Cleanflight.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

#include "platform.h"

#include "gpio.h"
#include "light_led.h"
#include "sound_beeper.h"
#include "bus_i2c.h"
#include "bus_spi.h"

#include "system.h"

// 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;

#ifdef STM32F303xC
// from system_stm32f30x.c
void SetSysClock(void);
#endif
#ifdef STM32F10X_MD
// from system_stm32f10x.c
void SetSysClock(bool overclock);
#endif

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(bool overclock)
{

#ifdef STM32F303xC
    // start fpu
    SCB->CPACR = (0x3 << (10*2)) | (0x3 << (11*2));
#endif

#ifdef STM32F303xC
    SetSysClock();
#endif
#ifdef STM32F10X_MD
    // Configure the System clock frequency, HCLK, PCLK2 and PCLK1 prescalers
    // Configure the Flash Latency cycles and enable prefetch buffer
    SetSysClock(overclock);
#endif

    // Configure NVIC preempt/priority groups
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);

#ifdef STM32F10X_MD
    // Turn on clocks for stuff we use
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
#endif

    RCC_ClearFlag();


    enableGPIOPowerUsageAndNoiseReductions();


#ifdef STM32F10X_MD
    // Turn off JTAG port 'cause we're using the GPIO for leds
#define AFIO_MAPR_SWJ_CFG_NO_JTAG_SW            (0x2 << 24)
    AFIO->MAPR |= AFIO_MAPR_SWJ_CFG_NO_JTAG_SW;
#endif

    ledInit();
    beeperInit();

    // Init cycle counter
    cycleCounterInit();

    // SysTick
    SysTick_Config(SystemCoreClock / 1000);

#ifdef CC3D
    spiInit(SPI1);
    spiInit(SPI2);
#endif

#ifndef CC3D
    // Configure the rest of the stuff
    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);
}

// FIXME replace mode with an enum so usage can be tracked, currently mode is a magic number
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;
    }
}