stm32输出一路0-100kHz的矩形波信号，占空比1%-70%可调的示例代码

以下是一个简单的示例代码，可以实现输出一路0-100kHz的矩形波信号，占空比为1%-70%可调。

#include "stm32f4xx.h"

#define PWM_FREQ 100000 // PWM输出频率
#define PWM_MAX_DUTY 8400 // PWM最大占空比

void TIM_Configuration(void)
{
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef TIM_OCInitStructure;
    uint16_t PrescalerValue = 0;
    uint16_t TimerPeriod = 0;
    uint16_t Channel2Pulse = 0;

    // 使能定时器时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

    // 定时器配置
    TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseStructure.TIM_Period = TimerPeriod;
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    // 配置定时器输出比较通道2
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;
    TIM_OCInitStructure.TIM_Pulse = Channel2Pulse;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
    TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
    TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset;
    TIM_OC2Init(TIM3, &TIM_OCInitStructure);

    // 预装载比较值和周期值
    TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
    TIM_ARRPreloadConfig(TIM3, ENABLE);

    // 配置定时器中断优先级
    NVIC_InitTypeDef NVIC_InitStructure;
    NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    // 启动定时器
    TIM_Cmd(TIM3, ENABLE);
}

void TIM3_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
    {
        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
    }
}

void PWM_SetDutyCycle(uint16_t duty)
{
    // 计算比较值
    uint16_t channel2pulse = (duty * PWM_MAX_DUTY) / 100;
    TIM_SetCompare2(TIM3, channel2pulse);
}

int main(void)
{
    // 初始化定时器
    TIM_Configuration();

    // 设置PWM输出频率
    uint16_t PrescalerValue = (uint16_t)(SystemCoreClock / 2 / PWM_FREQ) - 1;
    uint16_t TimerPeriod = (uint16_t)(SystemCoreClock / 2 / (PrescalerValue + 1) / PWM_FREQ) - 1;
    TIM_PrescalerConfig(TIM3, PrescalerValue, TIM_PSCReloadMode_Immediate);
    TIM_SetAutoreload(TIM3, TimerPeriod);

    // 设置PWM占空比
    uint16_t duty = 50; // 初始占空比为50%
    PWM_SetDutyCycle(duty);

    while (1)
    {
        // 模拟占空比调节
        duty += 10;
        if (duty > 70)
        {
            duty = 10;
        }
        PWM_SetDutyCycle(duty);
        delay_ms(100);
    }
}

需要注意的是，示例代码中使用了一个自定义的函数`PWM_SetDutyCycle()`来设置PWM占空比。在该函数中，我们根据当前占空比和PWM最大占空比计算出比较值，并通过`TIM_SetCompare2()`函数设置到定时器比较通道2的比较寄存器中，从而实现占空比的调节。另外，为了方便占空比的调节，我们在`main()`函数中使用了一个简单的循环来模拟占空比的变化。