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Piccolo SPI CS

Mehmet_Akif Ceylan
Intellectual 310 points
Other Parts Discussed in Thread: CONTROLSUITE

Hi,

I've searched too many posts on the forum but I could not find exact solution.

I am trying to communicate with MCP41010 digital pot through SPI of F28069. When I configured SPI as standart MISO, MOSI, CLK, CS I could not communicate with it. If I use CS as GPIO and add delays after loading data to FIFO buffer, it seems ok. Around 950 count "for loop" well suited.

My question is about here, what is the best method to control SPISTE pin?

I could not control the RX FIFO Status because, there is no returning from MCP41010 chip. I tried to find TXFIFO related method but I can't. Is there any method to control all TXFIFO buffer has sent?

Also, it would be very nice if I could set delay between last clock and SPISTEB, but I think there is no register for that purpose.

Thanks.

  • 0
    Guru 30330 points
    Mehmet,

    Is the C28x SPI configured as the master?

    You have a few options to control the SPISTE pin. One way is to allow the SPI module to control when it is set active. If you are using the FIFO, and keeping it full, the SPISTE will stay active until all words are transmitted.

    The other option is is use any GPIO as a replacement for the SPISTE pin. This is the custom chip select. If you require specific timings, or want to always be in control of when the slave is active, you can just drive the CS active and send your data.

    Have you looked at the controlSuite examples for SPI interrupts? I am not sure what you are trying to achieve with the "method to control all TXFIFO buffer has sent". Are you trying to keep track of the total number of words sent? Are you trying to find out when the TXFIFO is empty in order to reload it?

    You are correct in your last statement about a delay between the last clock and SPISTE. If you do require a longer time before SPISTE goes inactive, your best bet is likely to use the GPIO method. There are various posts on E2E regarding this scenario.

    Regards,
    Mark
  • 0 in reply to Mark Labbato
    Guru 30330 points
    Mehmet,

    Do you have any other questions? If not, please let me know so that I may close this post.

    Thanks,
    Mark