如何配置定时器，使PWM频率不会随着系统时钟的变化而变化

只看该作者 · 2022-4-14 19:49

在调试PWM波时，有时候会切换系统时钟，导致PWM的频率也变化；

在配置定时器时，通过获取定时器的时钟来配置定时器，可避免PWM频率随着系统时钟的变化而变化。

测试代码如下：

int main(void)

{

GPIO_Config_T GPIO_ConfigStruct;

TMR_BaseConfig_T TMR_TimeBaseStruct;

TMR_OCConfig_T OCcongigStruct;

//RCM_Reset();

uint32_tpclk1_value=0,pclk2_value;

RCM_ReadPCLKFreq(&pclk1_value,&pclk2_value);

RCM_EnableAPB2PeriphClock((RCM_APB2_PERIPH_T)(RCM_APB2_PERIPH_GPIOA |RCM_APB2_PERIPH_TMR1 | RCM_APB2_PERIPH_GPIOB));

GPIO_ConfigStruct.pin = GPIO_PIN_13;

GPIO_ConfigStruct.mode= GPIO_MODE_AF_PP;

GPIO_ConfigStruct.speed = GPIO_SPEED_50MHz;

GPIO_Config(GPIOB, &GPIO_ConfigStruct);

GPIO_ConfigStruct.pin = GPIO_PIN_8;

GPIO_Config(GPIOA, &GPIO_ConfigStruct);

TMR_TimeBaseStruct.clockDivision = TMR_CLOCK_DIV_1;

TMR_TimeBaseStruct.countMode = TMR_COUNTER_MODE_UP;

TMR_TimeBaseStruct.division = (pclk2_value/100000-1);

//TMR_TimeBaseStruct.division =720-1;

TMR_TimeBaseStruct.period = 10-1;

TMR_ConfigTimeBase(TMR1, &TMR_TimeBaseStruct);

OCcongigStruct.idleState = TMR_OC_IDLE_STATE_RESET;

OCcongigStruct.mode = TMR_OC_MODE_PWM1;

OCcongigStruct.nIdleState = TMR_OC_NIDLE_STATE_RESET;

OCcongigStruct.nPolarity = TMR_OC_NPOLARITY_HIGH;

OCcongigStruct.outputNState = TMR_OC_NSTATE_ENABLE;

OCcongigStruct.outputState = TMR_OC_STATE_ENABLE;

OCcongigStruct.polarity = TMR_OC_POLARITY_HIGH;

OCcongigStruct.pulse = 3;

TMR_ConfigOC1(TMR1,&OCcongigStruct);

TMR_ConfigOC1Preload(TMR1, TMR_OC_PRELOAD_ENABLE);

TMR_EnableAutoReload(TMR1);

TMR_Enable(TMR1);

TMR_EnablePWMOutputs(TMR1);

while(1)

{

}

具体内容，请查看附件。

只看该作者 · 2022-4-18 15:47

下载学习学习

只看该作者 · 2022-4-19 08:04

学习了，谢谢分享。