STM32 simple and easy accurate delay (only one timer is needed)

weizhongc

STM32 simple and easy accurate delay (only one timer is needed) [Copy link]

When I was testing an analog i2c, I was annoyed that the tick timer was used and there was no precise delay of us. I wrote one on impulse, which is very simple and easy to use. The system clock is 72M. The routine is as follows

1. void delay_init(void) { TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE); //Clock enable //Timer TIM4 initialization TIM_TimeBaseStructure.TIM_Period = 40000; //Set the value of the auto-reload register period to load the activity at the next update event TIM_TimeBaseStructure.TIM_Prescaler = 0; //Set the prescaler value used as the divisor of the TIMx clock frequency TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1; //Set the clock division: TDTS = Tck_tim TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //TIM up counting mode TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure); //Initialize the time base unit of TIMx according to the specified parameters } //Maximum delay 65536/72 = 910 us void delay_us(uint32 nTime) { /* Clear the counter and enable the timer*/ nTime*=72; TIM4->CNT = 0; TIM_Cmd（TIM4，ENABLE）; while( (TIM4->CNT) < nTime); TIM_ClearFlag(TIM4, TIM_FLAG_Update); TIM_Cmd（TIM4，DISABLE）; } void delay_ms(u16 ms) { while(ms--) { delay_us(500); delay_us(500); } }

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ljj3166

It is a rogue to delay the timer without giving the clock configuration

网络孤客

What frequency does the system clock use?

weizhongc

ljj3166 posted on 2017-11-7 15:24 It is a rogue to use a timer delay without giving the clock configuration

Yes, 0 frequency division

weizhongc

Network loner posted on 2017-11-7 16:24 What frequency does the system clock use?

It uses 72M

weizhongc

In fact, there are many things in the program that affect the delay, so it cannot be said to be an accurate delay.

花舞阙康

I just started learning STM32 from scratch, it looks very good. Thank you.

weizhongc

Happy holidays to the host