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CCS/TMS570LC4357: Need the Understanding for the DMA Offset

Part Number: TMS570LC4357

Tool/software: Code Composer Studio

Hi Team,

While integrating the SPI with DMA i found that, it is required for you to add the offset to the source address if you are transmitting the SPI packet through the DMA, which is 2 for the case of SPI whereas it is 3 for the SCI module.

Why there is such a need that we have to add the offset for the same? How would it differ for the other modules?

Regards,

Shivam Kakad

  • Hello,

    1. For SPI, the transmit data is written to bit[15:0] of SPIDATA1. TMS570LC4357 supports big-endian format, so the data is located at 2nd byte in memory

    2. For SCI, the TX data is bit[7:0] of SCITD register, so it is the 3rd byte in memory.