stm32初始化定时器4通道3pwm

以下是使用STM32初始化定时器4通道3PWM的示例代码：

#include "stm32f4xx.h"

void TIM4_CH3_PWM_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStruct;
    TIM_OCInitTypeDef TIM_OCInitStruct;

    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_8;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOB, &GPIO_InitStruct);
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource8, GPIO_AF_TIM4);

    TIM_TimeBaseStruct.TIM_Period = 1000 - 1;
    TIM_TimeBaseStruct.TIM_Prescaler = 84 - 1;
    TIM_TimeBaseStruct.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStruct.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStruct);

    TIM_OCInitStruct.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStruct.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStruct.TIM_Pulse = 500 - 1;
    TIM_OCInitStruct.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC3Init(TIM4, &TIM_OCInitStruct);

    TIM_Cmd(TIM4, ENABLE);
    TIM_CtrlPWMOutputs(TIM4, ENABLE);
}

int main(void)
{
    TIM4_CH3_PWM_Init();

    while (1)
    {
        // do something
    }
}

在以上示例代码中，我们使用了定时器4的通道3来生成PWM信号。首先，我们需要初始化GPIO口和定时器4。然后，我们设置定时器4的时基，这里我们设置周期为1000，预分频系数为84，这样就可以得到1kHz的PWM信号。接着，我们配置通道3为PWM输出模式，并设置PWM的占空比为50%。最后，我们使能定时器4和PWM输出。在主循环中，我们可以添加其他的代码，例如读取传感器数据等。