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TMS320F280039C: CLB_OUTPUTXBAR cannot override EPWM pin but OUTPUTXBAR can override

Julia Li
Expert 4385 points
Part Number: TMS320F280039C
Other Parts Discussed in Thread: SYSCONFIG

Hi Champs,

I ask this for our customer.

Now customer wants to use CLB to process EPWM5 signals, they configure GPIO8 as EPWM5A and configure GPIO9 as EPWM5B. They hope to use CLB output signal to directly overwrite the original EPWM5A/EPWM5B signal so they configure CLB_OUTPUTXBAR for GPIO8 and OUTPUTXBAR for GPIO9. But they found GPIO9 can be overrided successfully, GPIO8 is still output EPWM5A original signal.

I can also simply reproduce the customer's problem on my side. In order to observation, I set CLB1_OUT0 and CLB1_OUT5 to constant 1, and configure CLB_OUTPUTXBAR for GPIO8 and OUTPUTXBAR as below. I found GPIO9 is 3.3V but GPIO8 is still OUTPUT EPWM signal.

But TRM said  CLB Output X-BAR architecture is identical to the architecture of the GPIO Output X-BAR. Can you also configure it on your side to see if this happens? If so, how can customer successfully override EPWM5A(GPIO8)? Due to PCB limitations, customers currently do not have other GPIO resources for outputting EPWM5A after CLB processing.

Thanks!

Julia

  • 0
    TI__Mastermind 27440 points

    Hi Julia,

    It is not necessary to use the XBARs to override the PWM signal. The GPIO mux should be configured to send EPWM5A/EPWM5B to the pin, but internally this signal is being overrided by the CLB through the TILE module in SysConfig. Let me know if this makes sense.

    Thank you,

    Luke

  • 0 in reply to Luke Jones
    TI__Expert 4385 points

    Hi Luke,

    Yes now we configure GPIO8/9 to EPWM5A/EPWM5B. But it can only output EPWM5A/EPWM5B original signal if we don't configure XBAR. And it seems like CLB_OUTPUTXBAR and OUTPUTXBAR have different actions, one can override EPWM and the other cannot.

    Thanks!

    Julia

  • 0 in reply to Julia Li
    TI__Mastermind 27440 points

    Hi Julia,

    Could you send the .syscfg used to override the EPWM outputs without using the XBARs? I can check to make sure this was done correctly or if there is a possible bug in the CLB Output override table. You should not be using the XBARs for this use-case.

    Thank you,

    Luke

  • 0 in reply to Luke Jones
    TI__Expert 4385 points

    Hi Luke,

    Yes I know CLB can outout to EPWM, but it only connect to EPWM1-4, if I need to override EPWM5 I think I must use XBAR.

    You can check my project, here OUTPUTXBAR can cover EPWM5B, but CLB_OUTPUTXBAR cannot cover EPWM5A.

    7043.clb_ex8_external_signal_AND_gate.zip

    Thanks!

    Julia

  • +1 in reply to Julia Li
    TI__Mastermind 27440 points

    Hi Julia,

    Apologies for the misunderstanding, I assumed the CLB had the capability to override EPWM5. From looking at your project, it looks like you are still configuring EPWM5 through SysConfig, even though you're also configuring it manually in your main function. This is overriding the pinmux that was previousl owned by the CLB Output XBAR. If you remove the PWM from your sysconfig file, I expect this will resolve your issue.

    Thank you,

    Luke