正点原子stm32dac产生正弦波

要使用正点原子stm32dac产生正弦波，可以参考以下步骤：

1. 在正点原子stm32开发板上连接DAC输出引脚和示波器或音响等设备。

2. 使用stm32的定时器产生定时中断，在中断处理函数中更新DAC输出值。

3. 计算出正弦波的采样点值，并将其设置为DAC输出值。

4. 根据采样频率和正弦波的频率确定采样点数，通过循环计算出所有采样点的值。

5. 处理完所有采样点后，循环回到第一步，等待下一个定时中断。

以下是一个简单的代码示例，可以根据具体的硬件和需求进行修改：

#include <stm32f10x.h>

#define SAMPLE_RATE 44100
#define PI 3.1415926

volatile uint16_t dac_value = 0;
volatile int16_t sin_table[1024];

void DAC_Configuration(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  DAC_InitTypeDef DAC_InitStructure;

  /* Enable GPIOA clock */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
  
  /* Configure PA4 as analog */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Enable DAC clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);

  /* Configure DAC */
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T2_TRGO;
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
  DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bit0;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  DAC_Init(DAC_Channel_1, &DAC_InitStructure);

  /* Enable DAC channel */
  DAC_Cmd(DAC_Channel_1, ENABLE);
}

void TIM_Configuration(void)
{
  TIM_TimeBaseInitTypeDef TIM_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;

  /* Enable TIM2 clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);

  /* Configure TIM2 */
  TIM_DeInit(TIM2);
  TIM_InitStructure.TIM_Period = (SystemCoreClock / SAMPLE_RATE) - 1;
  TIM_InitStructure.TIM_Prescaler = 0;
  TIM_InitStructure.TIM_ClockDivision = 0;
  TIM_InitStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_InitStructure.TIM_RepetitionCounter = 0;
  TIM_TimeBaseInit(TIM2, &TIM_InitStructure);

  /* Enable TIM2 interrupt */
  TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);

  /* Configure NVIC */
  NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* Start TIM2 */
  TIM_Cmd(TIM2, ENABLE);
}

void generate_sin_table(void)
{
  int i;
  for (i = 0; i < 1024; i++) {
    sin_table[i] = (int16_t)(16383 * sin(2 * PI * i / 1024));
  }
}

void TIM2_IRQHandler(void)
{
  static uint32_t index = 0;
  DAC_SetChannel1Data(DAC_Align_12b_R, sin_table[index]);
  index = (index + 1) % 1024;
  TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
}

int main(void)
{
  /* Configure DAC and TIM */
  DAC_Configuration();
  TIM_Configuration();

  /* Generate sin table */
  generate_sin_table();

  while (1);
}