time.c

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/**
 * \file    heivs/time.c
 * \author  marc dot pignat at hevs dot ch
 *
 * Uses timer 7.
 */

#include "heivs/time.h"
#include "heivs/config.h"
#include "heivs/delay.h"
#include "stm32/stm32f4xx_tim.h"
#include "stm32/stm32f4xx_rcc.h"
#include "stm32/stm32f4xx_misc.h"

timeout_t time_set_timeout_ms(uint32_t ms)
{
    timeout_t time = time_get();
    time.value += ms;

    /* The timeout should be at least ms */
    time.value += 1;
    return time;
}

volatile uint32_t gTimeCounter = 0;

static void tim7_irq_handler(void)
{
    if (TIM7->SR & TIM_SR_UIF)
    {
        gTimeCounter++;
        TIM_ClearITPendingBit(TIM7, TIM_IT_Update);
    }
}

void time_suspend()
{
    TIM_ITConfig(TIM7, TIM_IT_Update, DISABLE);
    TIM_Cmd(TIM7, DISABLE);
}

void time_resume()
{
    TIM_ITConfig(TIM7, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM7, ENABLE);
}

void time_init(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

    gTimeCounter = 0;

    NVIC_InitStructure.NVIC_IRQChannel = TIM7_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 8;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_InitStructure.NVIC_Handler = tim7_irq_handler;
    NVIC_Init(&NVIC_InitStructure);

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM7, ENABLE);
    RCC_APB1PeriphClockLPModeCmd(RCC_APB1Periph_TIM7, ENABLE);
    /* From clock to 1 MHz */
    TIM_TimeBaseStructure.TIM_Prescaler = (SystemClock.hclk/1000000)/2 - 1;
    /* from 1 MHz to 1 KHz*/
    TIM_TimeBaseStructure.TIM_Period = 1000 - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM7, &TIM_TimeBaseStructure);
    time_resume();

#if !USE_BOOT_TIME_CRITICAL
    delay_wait_ms(500);
#endif
}

uint32_t time_diff_ms(timeout_t now, timeout_t before)
{
    return now.value - before.value;
}