STM32F4 USART DMA - Kein Restart

[Michael K. (mmike)]

Hallo zusammen,

ich versuche derzeit mit dem STM32F4 Discovery einen Block Daten per 
USART DMA zu übertragen.
Das funktioniert auch teilweise, dass einmalig die Daten übertragen 
werden. Danach stoppt der DMA Transfer wie gewünscht (Mode: normal, 
nicht circular), aber er lässt sich nicht erneut starten. Das Problem 
ist also, dass der DMA Transfer nur einmal startet, aber ein erneuter 
Start nicht wie gewollt ausgeführt wird.

Hier der Code:

Hier der Buffer der übertragen werden soll:

char txbuffer[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

Initialisierungsfunktion des USART3 auf GPIOB 10/11:

void USART3_INIT()
{
  /* Enable GPIO clock for UM6 USART*/
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);

  /* Enable USART clock */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);

  // Init GPIOs
  GPIO_InitTypeDef   GPIO_InitStructure;

  // Configure USART
  GPIO_InitStructure.GPIO_Pin               = GPIO_Pin_10 | GPIO_Pin_11;
  GPIO_InitStructure.GPIO_Mode               = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed               = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType               = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd               = GPIO_PuPd_UP;
  GPIO_Init(GPIOB, &GPIO_InitStructure);

  /* UM6 USART GPIO configuration -----------------------------------------------*/
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource10, GPIO_AF_USART3);
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource11, GPIO_AF_USART3);

  // Configure UM6 USART
  USART_InitTypeDef   USART_InitStructure;
  USART_InitStructure.USART_BaudRate             = 115200;
  USART_InitStructure.USART_WordLength           = USART_WordLength_8b;
  USART_InitStructure.USART_StopBits             = USART_StopBits_1;
  USART_InitStructure.USART_Parity             = USART_Parity_No;
  USART_InitStructure.USART_HardwareFlowControl       = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode               = USART_Mode_Rx | USART_Mode_Tx;
  USART_Init(USART3, &USART_InitStructure);

  // Enable receive interrupt on USART3
  USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);

  // Setup NVIC
  NVIC_InitTypeDef   NVIC_InitStructure;
  NVIC_InitStructure.NVIC_IRQChannel             = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority  = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority      = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd          = ENABLE;
  NVIC_Init(&NVIC_InitStructure);

  /* Enable USART */
  USART_Cmd(USART3, ENABLE);

  // Enable DMA TX for USART
  /* Enable the DMA clock */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);

  // Configure USART TX DMA
  DMA_InitTypeDef    dma_is;
  DMA_StructInit(&dma_is);                                  // Init dma structure (clear structure)
  dma_is.DMA_Channel                    = DMA_Channel_4;          // Select DMA channel (see reference manual, DMA1 request mapping)
  dma_is.DMA_Mode                      = DMA_Mode_Normal;          // Normal mode, not circular!
  dma_is.DMA_FIFOMode                    = DMA_FIFOMode_Disable;        // Disable FIFO mode
  //dma_is.DMA_FIFOThreshold                = DMA_FIFOThreshold_1QuarterFull;  // Irrelevant as direct mode is used (FIFO disabled)
  dma_is.DMA_DIR                      = DMA_DIR_MemoryToPeripheral;    // DMA direction definition (memory to peripheral)
  dma_is.DMA_Priority                    = DMA_Priority_Medium;        // Set priority
  dma_is.DMA_BufferSize                  = 10;                // Buffer size

  dma_is.DMA_Memory0BaseAddr                = (uint32_t)&txbuffer;        // Base address of buffer
  dma_is.DMA_MemoryInc                  = DMA_MemoryInc_Enable;        // Increment memory address enabled
  dma_is.DMA_MemoryBurst                  = DMA_MemoryBurst_Single;      // Set burst mode to single
  dma_is.DMA_MemoryDataSize                = DMA_MemoryDataSize_Byte;      // Set memory data size to BYTE

  dma_is.DMA_PeripheralBaseAddr              = (uint32_t)&(USART3->DR);      // Select peripheral base address (USART data register)
  dma_is.DMA_PeripheralInc                = DMA_PeripheralInc_Disable;    // Increment peripheral address disabled
  dma_is.DMA_PeripheralBurst                = DMA_PeripheralBurst_Single;    // Set peripheral burst mode to single
  dma_is.DMA_PeripheralDataSize              = DMA_PeripheralDataSize_Byte;    // Set peripheral data size to BYTE

  DMA_Init(DMA1_Stream3, &dma_is);                              // Init DMA

  USART_DMACmd(USART3, USART_DMAReq_Tx, ENABLE);                        // Enable USART DMA TX Requsts

  // Enable TX DMA transfer complete interrupt
  //DMA_ITConfig(USARTy_TX_DMA_STREAM, DMA_IT_TC, ENABLE);
}

und letztlich noch die Main:

int main(void)
{
  // Locals

  // ----------------------------------------------------------------------------------------------------------
  // Board initialization
  // ----------------------------------------------------------------------------------------------------------
  // Init LEDs
  LED_INIT();

  // Init serial port
  USART_INIT();

  // ----------------------------------------------------------------------------------------------------------
  // ----------------------------------------------------------------------------------------------------------
  // PRODUCTIVE LOOP
  // ----------------------------------------------------------------------------------------------------------
  // ----------------------------------------------------------------------------------------------------------
  int i = 0;
  int led = 0;

    while(1)
    {
      Delay(500000);
      LED1_ON;
      Delay(500000);
      LED1_OFF;

      if (i++ > 5)
      {
        StartDMA();
        i = 0;
      }
    }
}


/***************************************************************************************************************/
void Delay(__IO uint32_t nCount)
{
  while(nCount--)
  {
  }
}

Über einen hilfreichen Tipp würde ich mich sehr freuen!

mit besten Grüßen,
Michael

[Stm M. (stmfresser)]

Hallo!

ich glaube es DMA Mode soll circular sein.

  dma_is.DMA_Mode                      = DMA_Mode_Normal;          //

VG

[RP6conrad (Gast)]

Code von  StartDMA() ?
Mit meinen DiscoveryF100 functioniert es so :

char bufferTx[254] = "USART DMA Polling: USARTy -> USARTz using DMA";
 char bufferRx[127] = "USART DMA Polling: USARTz -> USARTy using DMA";
 void DMA_Configuration(void)
 {
  DMA_InitTypeDef DMA_InitStructure;
  /* USARTy TX DMA1 Channel (triggered by USARTy Tx event) Config */
  DMA_DeInit( DMA1_Channel4);  
  DMA_InitStructure.DMA_PeripheralBaseAddr =  0x40013804 ;//USART1_DR_Base
  DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)bufferTx;
  DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
  DMA_InitStructure.DMA_BufferSize = 10;
  DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Priority = DMA_Priority_Low;
  DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
  DMA_Init( DMA1_Channel4, &DMA_InitStructure);
  }
 /* Enable USARTy DMA TX request */
 USART_DMACmd(USART1,USART_DMAReq_Tx, ENABLE);
 /* Enable USARTy TX DMA1 Channel */
 DMA_Cmd(DMA1_Channel4, ENABLE);
 USART_Cmd(USART1, ENABLE);
 void Start_DMA(int string_length){
  //Wait until USARTy TX DMA1 Channel Transfer Complete 
       if (DMA_GetFlagStatus(DMA1_FLAG_TC4) == SET){
         DMA1_Channel4->CCR &= ~DMA_CCR_EN;      // disable DMA
         DMA1_Channel4->CMAR  =  (uint32_t)bufferTx;//(unsigned)
         DMA1_Channel4->CNDTR = string_length;//strlen(hallo);
         DMA1_Channel4->CCR |= DMA_CCR_EN; 
       }
  }