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DMA UART1 TX

Question asked by S S on Jun 25, 2019
Latest reply on Jun 28, 2019 by xiangjun.rong

Hi,

As we mentioned earlier, we are using LPC4357. We have connected an embedded ethernet module to UART1. We are planning to use DMA for both RX and TX. To transmit a packet via DMA we have called

Chip_GPDMA_Transfer function.  We are using ethernet to communicate with a socket based server application. The server App is receiving whatever is in that uartABStart – buffer.

Sample code

 

dmaChannelNumTx = Chip_GPDMA_GetFreeChannel(LPC_GPDMA, _GPDMA_CONN_UART_Tx);

Chip_GPDMA_Transfer(LPC_GPDMA, dmaChannelNumTx,

                                                                                  (uint32_t) &uartABStart[0],

                                                                                  _GPDMA_CONN_UART_Tx,

                                                                                  GPDMA_TRANSFERTYPE_M2P_CONTROLLER_DMA,

                                                                                  sizeof(uartABStart));

 

Now the question is, Do we need to call  Chip_GPDMA_Transfer function Whenever we want to send a packet via DMA?  Since that function call sets up that channel , is there different method to trigger DMA by giving the source address and  size?

Thanks

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