stm32 pwm输出正弦波

可以通过配置定时器的PWM输出来实现stm32的正弦波输出。具体步骤如下：
1. 配置定时器的时钟源和分频系数，使得定时器的计数频率为所需的正弦波频率的若干倍。
2. 配置定时器的PWM输出模式为PWM模式1或2，使得PWM输出的占空比可以通过CCR寄存器的值来控制。
3. 准备一个正弦波表，将正弦波表中的值作为CCR寄存器的值，即可实现PWM输出正弦波。

下面是一个示例代码，实现了以TIM1_CH1为例的PWM输出正弦波：

// 正弦波表，共37个值
const uint16_t sinWave[37] = {2048, 2447, 2831, 3185, 3495, 3750, 3939, 4056, 4095, 4056, 3939, 3750, 3495, 3185, 2831, 2447, 2048, 1649, 1265, 911, 601, 346, 157, 40, 0, 40, 157, 346, 601, 911, 1265, 1649, 2048, 2447, 2831, 3185, 3495, 3750, 3939};

// 定时器中断处理函数
void TIM1_UP_IRQHandler(void) {
    if (TIM_GetITStatus(TIM1, TIM_IT_Update) != RESET) {
        static uint8_t index = 0;
        index++;
        if (index >= 37) {
            index = 0;
        }
        TIM1->CCR1 = sinWave[index];
        TIM_ClearITPendingBit(TIM1, TIM_IT_Update);
    }
}

// 初始化定时器1，PWM输出正弦波
void TIM1_PWM_Init(void) {
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;    TIM_OCInitTypeDef TIM_OCInitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

    TIM_TimeBaseStructure.TIM_Period = 4095; // PWM周期为4096个计数器时钟
    TIM_TimeBaseStructure.TIM_Prescaler = 0; // 不分频
    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM1, &TIM_OCInitStructure);

    TIM_ITConfig(TIM1, TIM_IT_Update, ENABLE);

    NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    TIM_Cmd(TIM1, ENABLE);
}