求助，关于STM32F407的DMA疑问求解

使用库文件的Demo程序，配合ST官方Demo板，

下载库文件的Demo程序，发送使用DMA时，DAC没有输出，
反复修改，
最后将两个DAC都配置成Stream5 Chanel7 两个通道都正常输出，

但是数据手册了上DAC2应该是Sream6 Channel7,   根据手册配置的话 DAC1和DAC2 都没有输出

这是怎么回事，

下边是我的源程序

/**
  ******************************************************************************
  * @file    DAC_SignalsGeneration/main.c
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    19-September-2011
  * @brief   Main program body.
  ******************************************************************************
  * @attention
  *
  * THE PRESENT FIRMWARE WHICH IS FOR GUIDANCE ONLY AIMS AT PROVIDING CUSTOMERS
  * WITH CODING INFORMATION REGARDING THEIR PRODUCTS IN ORDER FOR THEM TO SAVE
  * TIME. AS A RESULT, STMICROELECTRONICS SHALL NOT BE HELD LIABLE FOR ANY
  * DIRECT, INDIRECT OR CONSEQUENTIAL DAMAGES WITH RESPECT TO ANY CLAIMS ARISING
  * FROM THE CONTENT OF SUCH FIRMWARE AND/OR THE USE MADE BY CUSTOMERS OF THE
  * CODING INFORMATION CONTAINED HEREIN IN CONNECTION WITH THEIR PRODUCTS.
  *
  *

copy; COPYRIGHT 2011 STMicroelectronics
  ******************************************************************************  
  */

/* Includes ------------------------------------------------------------------*/
#include "STM32f4_discovery.h"

/** @addtogroup STM32F4_Discovery_Peripheral_Examples
  * @{
  */

/** @addtogroup DAC_SignalsGeneration
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define DAC_DHR12R2_ADDRESS    0x40007414
#define DAC_DHR8R1_ADDRESS     0x40007410

/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
DAC_InitTypeDef  DAC_InitStructure;

const uint16_t Sine12bit[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};
const uint8_t Escalator8bit[6] = {0x0,0X11,0X22,0X33,0X44,0xFF};

__IO uint8_t SelectedWavesForm = 1;
__IO uint8_t KeyPressed = SET;

/* Private function prototypes -----------------------------------------------*/
void TIM6_Config(void);

void DAC_Ch1_EscalatorConfig(void);
void DAC_Ch2_SineWaveConfig(void);

void DAC_Ch1_NoiseConfig(void);
void DAC_Ch2_TriangleConfig(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief   Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /*!< At this stage the microcontroller clock setting is already configured,
       this is done through SystemInit() function which is called from startup
       file (startup_stm32f4xx.s) before to branch to application main.
       To reconfigure the default setting of SystemInit() function, refer to
       system_stm32f4xx.c file
     */   

  /* Preconfiguration before using DAC----------------------------------------*/
  GPIO_InitTypeDef GPIO_InitStructure;

  /* DMA1 clock and GPIOA clock enable (to be used with DAC) */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1 | RCC_AHB1Periph_GPIOA, ENABLE);

  /* DAC Periph clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);

  /* DAC channel 1   2 (DAC_OUT1 = PA.4)(DAC_OUT2 = PA.5) configuration */
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA,  GPIO_InitStructure);

  /* TIM6 Configuration ------------------------------------------------------*/
  TIM6_Config();  

  /* Configures User Button */
  STM_EVAL_PBInit(BUTTON_USER, BUTTON_MODE_EXTI);

DAC_Ch1_EscalatorConfig();


        /* Sine Wave generator -----------------------------------------------*/
  DAC_Ch2_SineWaveConfig();

  while (1)
  {
    /* If the User Button is pressed */
    if (KeyPressed == RESET)
    {            
      DAC_DeInit();
    }

      /* select waves forms according to the Key Button status */
      if (SelectedWavesForm == 1)    //SelectedWavesForm 已经设置成1
      {
        /* The sine wave and the escalator wave has been selected */
       //   DAC_Ch1_EscalatorConfig();  ==========注释掉这部分，移动到while (1)前


        /* Escalator Wave generator ------------------------------------------*/
       // DAC_Ch2_SineWaveConfig();==========注释掉这部分，移动到while (1)前
      }
      else
      {
        /* The triangle wave and the noise wave has been selected */

        /* Noise Wave generator ----------------------------------------------*/
      //DAC_Ch1_NoiseConfig();

        /* Triangle Wave generator -------------------------------------------*/
        DAC_Ch2_TriangleConfig();
      }

      KeyPressed = SET;

  }
}

/**
  * @brief  TIM6 Configuration
  * @note   TIM6 configuration is based on CPU @168MHz and APB1 @42MHz
  * @note   TIM6 Update event occurs each 37.5MHz/256 = 16.406 KHz   
  * @param  None
  * @retval None
  */
void TIM6_Config(void)
{
  TIM_TimeBaseInitTypeDef    TIM_TimeBaseStructure;
  /* TIM6 Periph clock enable */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);

  /* Time base configuration */
  TIM_TimeBaseStructInit( TIM_TimeBaseStructure);
  TIM_TimeBaseStructure.TIM_Period = 0xFF;
  TIM_TimeBaseStructure.TIM_Prescaler = 0;
  TIM_TimeBaseStructure.TIM_ClockDivision = 0;
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInit(TIM6,  TIM_TimeBaseStructure);

  /* TIM6 TRGO selection */
  TIM_SelectOutputTrigger(TIM6, TIM_TRGOSource_Update);

  /* TIM6 enable counter */
  TIM_Cmd(TIM6, ENABLE);
}

/**
  * @brief  DAC  Channel2 SineWave Configuration
  * @param  None
  * @retval None
  */
void DAC_Ch2_SineWaveConfig(void)
{
  DMA_InitTypeDef DMA_InitStructure;

  /* DAC channel2 Configuration */
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  DAC_Init(DAC_Channel_2,  DAC_InitStructure);
//这部分注释应该有问题，手册上DAC2对应Stream6 Channel7
/* DMA1_Stream5 channel7 configuration **************************************/
  DMA_DeInit(DMA1_Stream5);
  DMA_InitStructure.DMA_Channel = DMA_Channel_7;  
  DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)DAC_DHR12R2_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t) Sine12bit;
  DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
  DMA_InitStructure.DMA_BufferSize = 32;
  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_High;
  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_Stream5,  DMA_InitStructure);

  /* Enable DMA1_Stream5 */
  DMA_Cmd(DMA1_Stream5, ENABLE);

  /* Enable DAC Channel2 */
  DAC_Cmd(DAC_Channel_2, ENABLE);

  /* Enable DMA for DAC Channel2 */
  DAC_DMACmd(DAC_Channel_2, ENABLE);
}

/**
  * @brief  DAC Channel1 Escalator Configuration
  * @param  None
  * @retval None
  */
void DAC_Ch1_EscalatorConfig(void)
{
  DMA_InitTypeDef DMA_InitStructure;

  /* DAC channel1 Configuration */
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_None;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  DAC_Init(DAC_Channel_1,  DAC_InitStructure);
//这部分注释应该有问题，手册上DAC2对应Stream5 Channel7
  /* DMA1_Stream6 channel7 configuration **************************************/  
  DMA_DeInit(DMA1_Stream5);
  DMA_InitStructure.DMA_Channel = DMA_Channel_7;  
  DMA_InitStructure.DMA_PeripheralBaseAddr = DAC_DHR8R1_ADDRESS;
  DMA_InitStructure.DMA_Memory0BaseAddr = (uint32_t) Escalator8bit;
  DMA_InitStructure.DMA_BufferSize = 6;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_DIR = DMA_DIR_MemoryToPeripheral;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
  DMA_InitStructure.DMA_Priority = DMA_Priority_High;
  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);   

  /* Enable DMA1_Stream6 */
  DMA_Cmd(DMA1_Stream6, ENABLE);

  /* Enable DAC Channel1 */
  DAC_Cmd(DAC_Channel_1, ENABLE);

  /* Enable DMA for DAC Channel1 */
  DAC_DMACmd(DAC_Channel_1, ENABLE);
}

/**
  * @brief  DAC Channel2 Triangle Configuration
  * @param  None
  * @retval None
  */
void DAC_Ch2_TriangleConfig(void)
{
/* DAC channel2 Configuration */
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Triangle;
  DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_TriangleAmplitude_1023;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  DAC_Init(DAC_Channel_2,  DAC_InitStructure);

  /* Enable DAC Channel2 */
  DAC_Cmd(DAC_Channel_2, ENABLE);

  /* Set DAC channel2 DHR12RD register */
  DAC_SetChannel2Data(DAC_Align_12b_R, 0x100);
}

/**
  * @brief  DAC  Channel1 Noise Configuration
  * @param  None
  * @retval None
  */
void DAC_Ch1_NoiseConfig(void)
{
/* DAC channel1 Configuration */
  DAC_InitStructure.DAC_Trigger = DAC_Trigger_T6_TRGO;
  DAC_InitStructure.DAC_WaveGeneration = DAC_WaveGeneration_Noise;
  DAC_InitStructure.DAC_LFSRUnmask_TriangleAmplitude = DAC_LFSRUnmask_Bits10_0;
  DAC_InitStructure.DAC_OutputBuffer = DAC_OutputBuffer_Enable;
  DAC_Init(DAC_Channel_1,  DAC_InitStructure);

  /* Enable DAC Channel1 */
  DAC_Cmd(DAC_Channel_1, ENABLE);

  /* Set DAC Channel1 DHR12L register */
  DAC_SetChannel1Data(DAC_Align_12b_L, 0x7FF0);
}

#ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t* file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %drn", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */

/**
  * @}
  */

/******************* (C) COPYRIGHT 2011 STMicroelectronics *****END OF FILE****/