stm32f103 dac 可调正弦波

要生成可调正弦波，您可以使用DAC（数字模拟转换器）和定时器来实现。下面是一个简单的代码示例，可以帮助您开始：

首先，配置DAC通道和定时器：

DAC_InitTypeDef DAC_InitStruct;
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
GPIO_InitTypeDef GPIO_InitStruct;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);

GPIO_InitStruct.GPIO_Pin = GPIO_Pin_4;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStruct);

DAC_InitStruct.DAC_Trigger = DAC_Trigger_T2_TRGO;
DAC_InitStruct.DAC_WaveGeneration = DAC_WaveGeneration_None;
DAC_InitStruct.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
DAC_Init(DAC_Channel_1, &DAC_InitStruct);

TIM_TimeBaseInitStruct.TIM_Prescaler = 0;
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStruct.TIM_Period = 720; // 1MHz / 720 = 1.39kHz
TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);

然后，在定时器中断处理程序中生成正弦波：

volatile uint16_t sine_wave[100] = {0, 71, 142, 213, 284, 354, 424, 493, 561, 628, 695, 760, 824, 888, 949, 1010, 1069, 1126, 1182, 1236, 1288, 1339, 1387, 1434, 1479, 1521, 1562, 1600, 1636, 1669, 1699, 1727, 1752, 1775, 1795, 1812, 1826, 1838, 1846, 1852, 1855, 1855, 1852, 1846, 1838, 1826, 1812, 1795, 1775, 1752, 1727, 1699, 1669, 1636, 1600, 1562, 1521, 1479, 1434, 1387, 1339, 1288, 1236, 1182, 1126, 1069, 1010, 949, 888, 824, 760, 695, 628, 561, 493, 424, 354, 284, 213, 142, 71, 0, 0, 0, 0, 0, 0, 0, 0, 0};

void TIM2_IRQHandler(void)
{
    static uint16_t phase = 0;

    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) {
        DAC_SetChannel1Data(DAC_Align_12b_R, sine_wave[phase]);

        phase++;
        if (phase >= 100) {
            phase = 0;
        }

        TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
    }
}

在这个代码示例中，我们生成一个100点的正弦波，并在定时器中断处理程序中输出这个波形。您可以通过更改`sine_wave`数组来生成不同频率的正弦波。在这个例子中，我们使用的是1MHz的定时器时钟，生成1.39kHz的正弦波。