想做一个DMA-DAC信号发生器 这点代码已经debug两天了 就是出不来波形 感觉自己心态都不好了 真心求指点啊~

#include "dac.h"
#define DAC_DHR12R2_ADDRESS 0x40007414


uint16_t aSine12bit[32] = {
                      2047, 2447, 2831, 3185, 3498, 3750, 3939, 4056, 4095, 4056,
                      3939, 3750, 3495, 3185, 2831, 2447, 2047, 1647, 1263, 909,
                      599, 344, 155, 38, 0, 38, 155, 344, 599, 909, 1263, 1647};
       
                                                               
                                                                                       
                                                                                       
void TIM2_Config(void)
{
  TIM_TimeBaseInitTypeDef    TIM_TimeBaseStructure;

  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);       
  TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
  TIM_TimeBaseStructure.TIM_Period =0xFF;            /*(72000000/256*2/1000); */      
  TIM_TimeBaseStructure.TIM_Prescaler = 0;      
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;   
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  
  TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);

  TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);

  TIM_Cmd(TIM2, ENABLE);

}


void Dac2_Init(void)
{  
       
       
  DMA_InitTypeDef DMA_InitStructure;
  DAC_InitTypeDef DAC_InitStructure;
  GPIO_InitTypeDef  GPIO_InitStructure;
       
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
       
       
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd =GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

       
  DAC_InitStructure.DAC_Trigger=DAC_Trigger_T2_TRGO;       
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  DAC_Init(DAC_Channel_2,&DAC_InitStructure);       


  DAC_SetChannel2Data(DAC_Align_12b_R, 0x100);

       
  DMA_DeInit(DMA1_Stream6);
  DMA_InitStructure.DMA_Channel = DMA_Channel_7;  
  DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR12R2_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t)&aSine12bit;
  DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
  DMA_InitStructure.DMA_BufferSize = 256;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
  DMA_InitStructure.DMA_FIFOMode = DMA_FIFOMode_Disable;         
  DMA_InitStructure.DMA_FIFOThreshold = DMA_FIFOThreshold_HalfFull;
  DMA_InitStructure.DMA_MemoryBurst = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst = DMA_PeripheralBurst_Single;
  DMA_Init(DMA1_Stream6, &DMA_InitStructure);
       
       
  DMA_Cmd(DMA1_Stream6, ENABLE);       
       

  DAC_Cmd(DAC_Channel_2, ENABLE);


  DAC_DMACmd(DAC_Channel_2, ENABLE);
       
       
}


之后就是在主函数里执行
  TIM2_Config();       
  Dac2_Init();


这两天也看了不少别人的例子 反复比较觉得写得都一样啊 为什么DAC输出的电平都不变呢。。。