Nucleo F746双ADC同步采样不能启动

单通道工作时是正常的，现在想AD1与AD2同步模式工作，但是一直不能启动，各位大神帮看看是什么问题：
static TIM_HandleTypeDef  Timer4Handle;
void Timer4_init()
{
    TIM_ClockConfigTypeDef TimerClockConfig;
    TIM_MasterConfigTypeDef sMasterConfig;
    __TIM4_CLK_ENABLE();
    //Timer init
    Timer4Handle.Instance = (TIM_TypeDef *)TIM4;
    Timer4Handle.Init.Prescaler = 0;
    Timer4Handle.Init.CounterMode = TIM_COUNTERMODE_UP;
    Timer4Handle.Init.Period = 108;
    Timer4Handle.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    //Timer4Handle.Init.RepetitionCounter = 0;
    //Timer4Handle.Channel = HAL_TIM_ACTIVE_CHANNEL_1;
    //Timer4Handle.hdma[0] = &DMA_ADC_Handle;
    HAL_TIM_Base_Init(&Timer4Handle);

    TimerClockConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
    HAL_TIM_ConfigClockSource(&Timer4Handle,&TimerClockConfig);

    sMasterConfig.MasterOutputTrigger = TIM_TRGO_UPDATE;
    sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
    HAL_TIMEx_MasterConfigSynchronization(&Timer4Handle, &sMasterConfig);
    //HAL_TIM_Base_Start(&Timer4Handle);
    HAL_TIM_Base_Start_IT(&Timer4Handle);

}
/* ADC1 init function */
ADC_HandleTypeDef hadc1;
ADC_HandleTypeDef hadc2;
DMA_HandleTypeDef hdma_adc1;
static void MX_ADC1_Init(void)
{

  ADC_MultiModeTypeDef multimode;
  ADC_ChannelConfTypeDef sConfig;

    /**Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
    */
  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.ScanConvMode = DISABLE;
  hadc1.Init.ContinuousConvMode = ENABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_RISING;
  hadc1.Init.ExternalTrigConv = ADC_EXTERNALTRIGCONV_T4_TRGO;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 1;
  hadc1.Init.DMAContinuousRequests = ENABLE;
  hadc1.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  HAL_ADC_Init(&hadc1);

    /**Configure the ADC multi-mode
    */
  multimode.Mode = ADC_DUALMODE_REGSIMULT;
  multimode.DMAAccessMode = ADC_DMAACCESSMODE_2;
  multimode.TwoSamplingDelay = ADC_TWOSAMPLINGDELAY_5CYCLES;
  HAL_ADCEx_MultiModeConfigChannel(&hadc1, &multimode);

    /**Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
    */
  sConfig.Channel = ADC_CHANNEL_10;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_15CYCLES;
  HAL_ADC_ConfigChannel(&hadc1, &sConfig);

}

/* ADC2 init function */
static void MX_ADC2_Init(void)
{

  ADC_MultiModeTypeDef multimode;
  ADC_ChannelConfTypeDef sConfig;

    /**Configure the global features of the ADC (Clock, Resolution, Data Alignment and number of conversion)
    */
  hadc2.Instance = ADC2;
  hadc2.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
  hadc2.Init.Resolution = ADC_RESOLUTION_12B;
  hadc2.Init.ScanConvMode = DISABLE;
  hadc2.Init.ContinuousConvMode = ENABLE;
  hadc2.Init.DiscontinuousConvMode = DISABLE;
  hadc2.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc2.Init.NbrOfConversion = 1;
  hadc2.Init.DMAContinuousRequests = ENABLE;
  hadc2.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
  HAL_ADC_Init(&hadc2);

    /**Configure the ADC multi-mode
    */
  multimode.Mode = ADC_DUALMODE_REGSIMULT;
  multimode.DMAAccessMode = ADC_DMAACCESSMODE_2;
  multimode.TwoSamplingDelay = ADC_TWOSAMPLINGDELAY_5CYCLES;
  HAL_ADCEx_MultiModeConfigChannel(&hadc2, &multimode);

    /**Configure for the selected ADC regular channel its corresponding rank in the sequencer and its sample time.
    */
  sConfig.Channel = ADC_CHANNEL_13;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_15CYCLES;
  HAL_ADC_ConfigChannel(&hadc2, &sConfig);

}
void HAL_ADC_MspInit(ADC_HandleTypeDef* hadc)
{

  GPIO_InitTypeDef GPIO_InitStruct;
  if(hadc->Instance==ADC1)
  {
  /* USER CODE BEGIN ADC1_MspInit 0 */

  /* USER CODE END ADC1_MspInit 0 */
    /* Peripheral clock enable */
    __HAL_RCC_ADC1_CLK_ENABLE();

    /**ADC1 GPIO Configuration   
    PC0     ------> ADC1_IN10
    */
    GPIO_InitStruct.Pin = GPIO_PIN_0;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

    /* Peripheral DMA init*/

    hdma_adc1.Instance = DMA2_Stream0;
    hdma_adc1.Init.Channel = DMA_CHANNEL_0;
    hdma_adc1.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_adc1.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_adc1.Init.MemInc = DMA_MINC_ENABLE;
    hdma_adc1.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;
    hdma_adc1.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;
    hdma_adc1.Init.Mode = DMA_NORMAL;
    hdma_adc1.Init.Priority = DMA_PRIORITY_VERY_HIGH;
    hdma_adc1.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    HAL_DMA_Init(&hdma_adc1);

    __HAL_LINKDMA(hadc,DMA_Handle,hdma_adc1);

  /* USER CODE BEGIN ADC1_MspInit 1 */

  /* USER CODE END ADC1_MspInit 1 */
  }
  else if(hadc->Instance==ADC2)
  {
  /* USER CODE BEGIN ADC2_MspInit 0 */

  /* USER CODE END ADC2_MspInit 0 */
    /* Peripheral clock enable */
    __HAL_RCC_ADC2_CLK_ENABLE();

    /**ADC2 GPIO Configuration   
    PC3     ------> ADC2_IN13
    */
    GPIO_InitStruct.Pin = GPIO_PIN_3;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /* USER CODE BEGIN ADC2_MspInit 1 */

  /* USER CODE END ADC2_MspInit 1 */
  }

}
void adc_init_2ch()
{
    HAL_ADC_MspInit(&hadc1);
    HAL_ADC_MspInit(&hadc2);
    MX_ADC1_Init();
    MX_ADC2_Init();

}

void adc_readn( uint32_t * data, uint32_t nelems)
{
    HAL_ADC_Start(&hadc2);
    HAL_ADCEx_MultiModeStart_DMA(&hadc1, (uint32_t *)data, nelems);
}

void DMA2_Stream0_IRQHandler(void)//ADC DMA
{
    /* USER CODE BEGIN DMA2_Stream2_IRQn 0 */
    tim4cnt++;
    if(__HAL_DMA_GET_IT_SOURCE(&DMA_ADC_Handle, DMA_IT_HT)) { //Half transfer
        tinterval = tmr.read_us();//Half DMA
        HAL_DMA_IRQHandler(&DMA_ADC_Handle);
        return;
    }
    if(__HAL_DMA_GET_IT_SOURCE(&DMA_ADC_Handle, DMA_IT_TC))//Full transfer
        tinterval=tmr.read_us() - tinterval;
    HAL_DMA_IRQHandler(&DMA_ADC_Handle);
}
void Interrupt_Init()
{
    NVIC_SetVector(DMA2_Stream0_IRQn, (uint32_t)DMA2_Stream0_IRQHandler);
    HAL_NVIC_EnableIRQ(DMA2_Stream0_IRQn);
}

#define SAMPLESADC (1024*3)
union {
    uint32_t D[SAMPLESADC];
    uint16_t C[SAMPLESADC*2];
} samples;


void main()
{
    Interrupt_Init();
    Timer4_init();

    adc_init_2ch();
    memset(samples.D,0x5A5A,sizeof samples.D);
    adc_readn(samples.D,SAMPLESADC);


}