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TMS570LS3137 mibSPI Chip Select

Charles Johnston
Expert 2690 points

Other Parts Discussed in Thread: HALCOGEN

Hello,

I am using a variation of your example_mibspiDma.c code that came with HALCoGen 3.04.00. 

I’m trying to talk to a DAC that expects 24 bits for command/address/data.  I set up a character length of 8 bits and a Transfer Group 0 buffer length of 3.  The rest of the HALCoGen is set up per the example.

The chip select goes low and the first 8 bits are sent.  The CS then goes high (inactive) for about 50 nsec, then inactive before sending the next 8 bits.  Then another 50 nsec CS deselection occurs before sending out the last 8 bits.  Then CS goes inactive.

Is there a way to keep CS active while sending all contents of a Transfer Group?

Thanks, Charlie Johnston

 

  • 0
    TI__Genius 14205 points

    Hi Charlie,

    Enable "Lock Transmission" under transfer group setting in HALCoGen. Note: THe Tool tip when you take your Mouse to Lock Transmission setting gives the details of different CS configurations you can have.

    On the delays you should be able to configure in "Mibspi Delay" Tab.

    Hope this helps!.

    Regards
    Prathap

  • 0 in reply to Prathap
    Expert 2690 points

    Hi Prathap,

    Yes - that works.  The tool tip is misleading - "Lock transmition to stop interrupt by higher priority group."  I thought  this was irrelavent since we were only using one TG, but checking this box also sets CSHOLD for the active buffers.

    Thanks for your help,

    Charlie