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How to interface SPI to CLA on 28035

Cam Buskell11
Prodigy 150 points

Hi all.

I am looking to use an SPI bus to sample a 24-bit, 100+kSPS ADC and make use of the CLA in the 28035 to process the data.  From there I want to save processed data to external Flash as well as output the data to an I2S DAC.

Looking at the block diagram of the 28035 I don't see a direct connection between SPI buffer and the CLA module.  Instead I would have to take the SPI buffer (which I assume is the 16-bit peripheral bus???) then load it into the 32-bit peripheral bus (CLA accessible) and then load it into the CLA module.

Is this the correct process?  Is there a better way to do it?

Is there any code examples of this process?

I am using the experimenters kit and have compiled and debugged through the spi_loopback and ClaAdcFirFlash examples, and have read through the CLA guide (SPRUGE6B).

Thanks in advance.

  • 0
    Guru 192875 points

    Hi Cam,

    Cam Buskell11 said:

    Instead I would have to take the SPI buffer (which I assume is the 16-bit peripheral bus???) then load it into the 32-bit peripheral bus (CLA accessible) and then load it into the CLA module.

    Is this the correct process?  Is there a better way to do it?

    I'm not sure whether the above is possible as if you look into the CLA Block diagram and its overview - very few peripherals have access to the Main CPU bus.

    There are no examples for the above implementation.

    I would like you to post the same in C2000 forum:

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    TI__Guru**** 173310 points
    Moving this to the C2000 forum.
  • 0 in reply to AartiG
    Prodigy 150 points

    Thanks for moving the post.  I hadn't realized I posted it somewhere other than the C2000 forums.

    What I'm looking for is the feasibility of my application using this chip, and these modules, in the way I have described.

    If you think it can't work, or there is a better way, or there are limitations to this path please let me know.

    Thanks all.

  • 0
    TI__Mastermind 20850 points
    Hi Cam,

    The CLA (on 28035) does not have direct access to the SPI peripherals, what you would have to do is setup the SPI to interrupt the main CPU every n (n = 1 to 4 depending on whether you use the FIFO), have the SPI interrupt service routine (ISR) transfer the data from the receive buffer to a variable(s) or array in the memory block called CpuToCla1MsgRam, trigger a CLA task and then have that task read that memory.

    On the 28035 you transfer data between the cpu and cla through 2 message rams, CpuToCla1 and Cla1ToCpuMsgRam.