adc和dac 弹性映射的使用

void dac_init(void)

{

        GPIO_InitType GPIO_InitStructure;



  /* Once the DAC channel is enabled, the corresponding GPIO pin is automatically 

     connected to the DAC converter. In order to avoid parasitic consumption, 

     the GPIO pin should be configured in analog */

  GPIO_InitStructure.GPIO_Pins =  GPIO_Pins_4;

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_ANALOG;

  GPIO_Init(GPIOA, &GPIO_InitStructure);

        

          GPIO_InitStructure.GPIO_Pins = GPIO_Pins_0|GPIO_Pins_1;                                 

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT_PP;

  GPIO_InitStructure.GPIO_MaxSpeed = GPIO_MaxSpeed_50MHz;        

  GPIO_Init(GPIOC, &GPIO_InitStructure);

  

  DAC_InitType                          DAC_InitStructure;

  DMA_InitType                          DMA_InitStructure;

  TMR_TimerBaseInitType    TMR_TimeBaseStructure;





  /* TIM4 Configuration */

  /* Time base configuration */

  TMR_TimeBaseStructInit(&TMR_TimeBaseStructure); 

  TMR_TimeBaseStructure.TMR_Period = 0x19;          

  TMR_TimeBaseStructure.TMR_DIV = 0x0;       

  TMR_TimeBaseStructure.TMR_ClockDivision = 0x0;    

  TMR_TimeBaseStructure.TMR_CounterMode = TMR_CounterDIR_Up;  

  TMR_TimeBaseInit(TMR4, &TMR_TimeBaseStructure);



  /* TIM4 TRGO selection */

  TMR_SelectOutputTrigger(TMR4, TMR_TRGOSource_Update);



  /* DAC channel1 Configuration */

  DAC_StructInit(&DAC_InitStructure);

  DAC_InitStructure.DAC_Trigger = DAC_Trigger_TMR4_TRGO;

  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;

  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Disable;

  DAC_Init(DAC_Channel_1, &DAC_InitStructure);



  /* DAC channel2 Configuration */

  DAC_Init(DAC_Channel_2, &DAC_InitStructure);



  /* Fill Sine32bit table */

  for (Idx = 0; Idx < 32; Idx++)

  { 

    DualSine12bit[Idx] = (Sine12bit[Idx] << 16) + (Sine12bit[Idx]);

  }



  /* DMA2 channel4 configuration */

  DMA_Reset(DMA2_Channel4);

  

  DMA_DefaultInitParaConfig(&DMA_InitStructure);

  DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR12RD_Address;

  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)&DualSine12bit;

  DMA_InitStructure.DMA_Direction = DMA_DIR_PERIPHERALDST;

  DMA_InitStructure.DMA_BufferSize = 32;

  DMA_InitStructure.DMA_PeripheralInc = DMA_PERIPHERALINC_DISABLE;

  DMA_InitStructure.DMA_MemoryInc = DMA_MEMORYINC_ENABLE;

  DMA_InitStructure.DMA_PeripheralDataWidth = DMA_PERIPHERALDATAWIDTH_WORD;

  DMA_InitStructure.DMA_MemoryDataWidth = DMA_MEMORYDATAWIDTH_WORD;

  DMA_InitStructure.DMA_Mode = DMA_MODE_CIRCULAR;

  DMA_InitStructure.DMA_Priority = DMA_PRIORITY_HIGH;

  DMA_InitStructure.DMA_MTOM = DMA_MEMTOMEM_DISABLE;



  DMA_Init(DMA2_Channel4, &DMA_InitStructure);

//  DMA_Flexible_Config(DMA2, Flex_Channel4, DMA_FLEXIBLE_DAC1);//开启DMA弹性映射，弹性映射必须要加上这个配置！

  /* Enable DMA2 Channel4 */

  DMA_ChannelEnable(DMA2_Channel4, ENABLE);



  /* Enable DAC Channel1: Once the DAC channel1 is enabled, PA.04 is 

     automatically connected to the DAC converter. */

  DAC_Ctrl(DAC_Channel_1, ENABLE);

  /* Enable DAC Channel2: Once the DAC channel2 is enabled, PA.05 is 

     automatically connected to the DAC converter. */

  DAC_Ctrl(DAC_Channel_2, ENABLE);



  /* Enable DMA for DAC Channel2 */

  DAC_DMACtrl(DAC_Channel_2, ENABLE);



  /* TIM2 enable counter */

  TMR_Cmd(TMR4, ENABLE);

}