delay.c

#include "stm32f10x.h"
#include "delay.h"

volatile static int ticks_delay = 0;
volatile static int ticks_millis = 0;
volatile static uint8_t millis_flag = 0;
volatile static uint8_t delay_flag = 0;

int start_millis(void)
{
    millis_flag = 1;
    TIM2->CR1 |= TIM_CR1_CEN; //turn timer on

    return ticks_millis;
}

void reset_millis(void)
{
    millis_flag = 0;
    TIM2->CR1 &= ~(TIM_CR1_CEN);
    ticks_millis = 0;
}

int play_millis(int time)
{
    millis_flag = 1;
    TIM2->CR1 |= TIM_CR1_CEN; //turn timer on

    if(ticks_millis > time)
    {
        reset_millis();
    }

    return ticks_millis;
}


void init_delay(void)
{
    RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;

    TIM2->PSC = 0;
    TIM2->ARR = 72; // 1Mhz for easy timing with uS and mS

    TIM2->CR1 |= TIM_CR1_URS;
    TIM2->DIER |= TIM_DIER_UIE;
    TIM2->EGR |= TIM_EGR_UG;

    NVIC_EnableIRQ(TIM2_IRQn);
}

void TIM2_IRQHandler()
{
    TIM2->SR &= ~TIM_SR_UIF;
    if(delay_flag)
    {
        ticks_delay++;
    }
    if(millis_flag)
    {
        ticks_millis++;
    }
}


void delayUs(int uS)
{
    ticks_delay = 0;
    delay_flag = 1;
    TIM2->CR1 |= TIM_CR1_CEN; //turn timer on

    while(ticks_delay < uS){}

    TIM2->CR1 &= ~TIM_CR1_CEN; //turn timer off
    delay_flag = 0;
}

void delayMs(int mS)
{
    ticks_delay = 0;
    delay_flag = 1;
    TIM2->CR1 |= TIM_CR1_CEN; //turn timer on

    while(ticks_delay < (mS * 1000)){}

    TIM2->CR1 &= ~TIM_CR1_CEN; //turn timer off
    delay_flag = 0;
}