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TMS320F28379D: SPI DMA

Imre Kiss1
Intellectual 520 points
Part Number: TMS320F28379D


Good morning,

I am trying to writeout a continuous stream of 160 two byte word using DAMA SPI. the bestI could do so far is 16 words continuous.  By continuous I mesn CS stays low for the entire duration of the 160word transfer.  I can load the DMA buffer but can't write it in one swoop. I tried the obvious like setting to continuous and such but nothing gets mepast 16words.

thanks

  • 0
    TI__Mastermind 21420 points

    Hi Imre,

    The TX FIFO in the SPI module is 16-deep. So likely the time to fill up the FIFO is causing enough delay for the CS to go back high between each 16. What TX FIFO level do you have configured? I'm not sure if a fully continuous stream is possible, but if it is you would need to do smaller writes to the TX FIFO with the DMA. For example, a DMA burst size of 1 and the TX FIFO level triggers every time there is at least 1/16 empty. 

    Best Regards,

    Delaney