stm32输出5v的pwm

在STM32中，可以使用定时器模块来输出PWM信号，并且可以通过改变定时器的预分频、计数器自动重装载值和比较值，来控制PWM波形的频率和占空比。如果需要输出5V的PWM信号，可以使用STM32的定时器模块结合一个适当的电平转换器来实现。

以下是一个简单的代码示例，使用TIM3定时器输出5V的PWM信号：

#include "stm32f4xx.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_tim.h"

int main(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;

    // Enable GPIO clock
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

    // Enable TIM3 clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

    // Configure GPIO pins (PB4 as TIM3_CH1 output)
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_Init(GPIOB, &GPIO_InitStructure);

    // Connect TIM3 pins to AF2
    GPIO_PinAFConfig(GPIOB, GPIO_PinSource4, GPIO_AF_TIM3);

    // Configure TIM3
    TIM_TimeBaseStructure.TIM_Period = 1000; // PWM frequency = 84MHz / 1000 = 84kHz
    TIM_TimeBaseStructure.TIM_Prescaler = 0;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    // Configure TIM3 channel 1 as PWM output
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 500; // PWM duty cycle = 500 / 1000 = 50%
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM3, &TIM_OCInitStructure);
    TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);

    // Start TIM3
    TIM_Cmd(TIM3, ENABLE);

    while (1) {}
}

这里使用的是TIM3定时器的通道1输出PWM信号，占空比为50%，频率为84kHz。需要注意的是，输出的PWM信号的电平为STM32的IO引脚电平，一般为3.3V，如果需要输出5V的PWM信号，可以使用一个电平转换器来将3.3V转换为5V。