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CCS/TM4C129ENCPDT: UDMA_MODE_PER_SCATTER_GATHER under TI-RTOS

aleksander levandovskiy
Prodigy 190 points
Part Number: TM4C129ENCPDT

Tool/software: Code Composer Studio

I see in the uartechodma example and read about  #define TI_DRIVERS_UART_DMA 1. And I see in the TI-RTOS UsersGuide.

And it is not clear how can  uart receive Data  with DMA SCATTER_GATHER. In the uart APIs(TI-RTOS UsersGuide) is nothing about SCATTER_GATHER.

In the DMA(TI-RTOS UsersGuide) can't find explanation. Driver? Is somebody knows the steps to implement  UDMA_MODE_PER_SCATTER_GATHER under TI-RTOS.

Thanks in adwance.

Alex

  • 0
    TI__Guru 72500 points
    The UART Echo example uses UDMA_MODE_BASIC. (Lines 131 and 159 of the file UARTTivaDMA.c) Are you wanting to implement UDMA_MODE_PER_SCATTER_GATHER, or just curious how it can be used?
  • 0 in reply to Bob Crosby
    Prodigy 190 points

    Hello Bob.

    Thanks for the promt answer.

    1. I looked in the uartecho.c; uartecho_readme.txt: TI_DRIVERS_UART_DMA=1; but in EK_TM4C129EXL.c I found this :

    #ifndef TI_DRIVERS_UART_DMA
    #define TI_DRIVERS_UART_DMA 0
    #endif

    I understood this, that I must  #define TI_DRIVERS_UART_DMA 1, than I have DMA Driver and DMA mode. Is that right and enogh? Some what else ?
    But how can I know, that UDMA_MODE_BASIC is used? Where can I see this?

    2.Yes I want implement UDMA_MODE_PER_SCATTER_GATHER for 5 Buffers ( 256 Byte)for UART port and look how can I make this. What I have to do? With

    wich functions? In which Files?  I need some point to point action order, how to implement this.

    Best regards

    Alex

  • 0 in reply to aleksander levandovskiy
    TI__Guru 72500 points

    aleksander levandovskiy said:
    I understood this, that I must  #define TI_DRIVERS_UART_DMA 1, than I have DMA Driver and DMA mode. Is that right and enogh?

    Yes, then the example will use the uDMA in basic mode.

    aleksander levandovskiy said:
    But how can I know, that UDMA_MODE_BASIC is used?

    Look at lines 131 and 159 of the file UARTTivaDMA.c in C:\ti\tirtos_tivac_2_16_01_14\products\tidrivers_tivac_2_16_01_13\packages\ti\drivers\uart.

    I will see if I can work up a demo for you.

  • 0 in reply to Bob Crosby
    Prodigy 190 points

    Hello Bob.

    Do you have some news for me?

    regards