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Original question:

MSPM0G3507: Can you please provide the steps to configure DMA for I2C send in controller mode.

MSPM0G3507: MSPM0G3519

hui_zhu
Prodigy 110 points
Part Number: MSPM0G3507
Other Parts Discussed in Thread: MSPM0G3519

Tool/software:

i2c_target_rw_multibyte_fifo_interrupts_LP_MSPM0G3519_nortos_ticlang.rar

I am currently debugging IIC communication through the launchpad. Sending data through IIC0 and receiving data through IIC2. Two interfaces can receive data normally through interrupt mode. But changing IIC2 to DMA mode, data reception cannot be completed. Can you provide an example of IIC transmitting and receiving data through DMA? Please help locate the issue in the attachment the code I modified. thank you.

  • 0
    Guru 101095 points

    Which side of the I2C is this operating? The name says "target" but the code all seems to be acting as a controller.

    -------------

    More generally:

    >  gTxCount0 = DL_I2C_fillControllerTXFIFO(I2C_0_INST, &gTxPacket0[0], gTxLen0);

    The DMA transfers from memory to the FIFO, so you shouldn't pre-fill the FIFO here. Doing this throws the (DMA vs I2C) counts off.

    --------------

    In addition to the suggestions in the thread you referenced, it might be useful to start with the SPI_send() function in example "spi_controller_repeated_fifo_dma_interrupt" here:

    https://dev.ti.com/tirex/explore/node?node=A__AC8uwWRQ8P8dtELVi9opaA__MSPM0-SDK__a3PaaoK__LATEST

    Two subtle points here:

    1) Since SPI is bi-directional, that function sets up both Tx and Rx DMA channels. The I2C will only use one or the other for any given transaction.

    2) For SPI, the initial Tx trigger is always "primed", so enabling the DMA immediately starts the transaction. For I2C, this won't happen until you call DL_I2C_startControllerTransfer().