Delay function using timers

[d4ng3r09]

Posted on June 04, 2014 at 18:42

Hi, 

i want to make a  delay function using timers using stm32f4 discovery.Unfortunatelly i have no idea the start. I read the timers doucmentation but it didn''t help me a lot.

Can anyone guide me please?

[Tesla DeLorean]

Posted on June 04, 2014 at 20:24

Spin loops, or interrupting?

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[d4ng3r09]

Posted on June 04, 2014 at 22:46

Actually i managed to get something work but not like i wanted to . i am supposed to make a delay of 10 secs and i am getting a delay of 28 secs.This is how thought getting working things

Since my bus clock is 42 MHZ i managed to reduce it to 1 KHZ .It means that have a period of 10^(-3).So to get 10 seconds , i have to make a counter with 10000 as a value. Can you tell what i missing? Thank you for your concern.

#include <stm32f4xx_gpio.h>
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_tim.h>
void
configLED() {
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
GPIO_InitTypeDef GPIO_InitStruct;
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStruct);
}
void
configTimerAndGpio() {
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
GPIO_InitTypeDef GPIO_InitStruct;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_3;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStruct.GPIO_OType = GPIO_OType_OD;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOB, &GPIO_InitStruct);
GPIO_PinAFConfig(GPIOB, GPIO_Pin_3, GPIO_AF_TIM2);
// TIM_TimeBaseInitStruct.TIM_Period = 10000;
TIM_TimeBaseInitStruct.TIM_Period = 1;
TIM_TimeBaseInitStruct.TIM_Prescaler = 42000-1;
TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Down;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
//TIM_PrescalerConfig()
}
void
delay() {
TIM_SetCounter(TIM2, 10000);
TIM_Cmd(TIM2, ENABLE);
/*while (TIM_GetFlagStatus(TIM2, TIM_FLAG_Update) != RESET) {
TIM_ClearFlag(TIM2, TIM_FLAG_Update);
}*/
while
(TIM_GetCounter(TIM2) > 1) {
}
TIM_Cmd(TIM2, DISABLE);
}
int
main(
void
) {
configTimerAndGpio();
configLED();
while
(1) {
GPIO_SetBits(GPIOA, GPIO_Pin_9);
delay();
GPIO_ResetBits(GPIOA, GPIO_Pin_9);
delay();
}
}