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BOOSTXL-CC3120MOD: Image programming through uart

Part Number: BOOSTXL-CC3120MOD
Other Parts Discussed in Thread: CC3120, , CC3120BOOST

Hello,

I am trying to program the flash image of my C3120 using the UART as described in http://www.ti.com/lit/ug/swpa230a/swpa230a.pdf. I can't seem to get the Ack signal after resetting the device through the nHIB pin. I'm setting the Rx line to continuous spaced values (0V) and resetting the device but nothing seems to happen. Am I misunderstanding what the break signal is? 

Thanks

  • Hi,

    Toggling the nHIB pin should be enough for the device to send an ACK signal, assuming it detects the break signal on power on. The break signal is indeed simply holding the RX line at 0V. From what you've described doing, that should be enough for the CC3120 to send at least an ACK on its UART TX line.

    What is your test setup? Are you using a CC3120 boosterpack? What are you using as the UART interface between your PC and the CC3120? How are you wiring that up?

    Regards,

    Michael

  • Thanks for the response,

    I'm using my F28379D launchpad with the BOOSTXL-CC3120MOD pack attached on headers J1-J4. All C2000 does right now is pull its Tx line low, triggers the pulls the nHIB high and then looks for the ACK response in the FIFO but it appear to be empty so it just gets stuck waiting for a signal. The uart on the is setup as: Baud rate of 921600bps, 8 bits, No parity,1 stop bit, FIFO enabled. I can post the code if that helps. 

    Also, to pull the c2000 Tx pin low I have it muxed as a gpio then I change it back to a SCI line.

  • Hi,

    Have you used a logic analyzer to probe the physical UART signals between the CC3120 and the C2000 you are using? Observing that would allow us to see if the interface is behaving correctly, and if perhaps there is something in your C2000 code that might be incorrect instead. If you could capture those signals and show me a screenshot of what you see that would be helpful for debug.

    Thanks,

    Michael

  • I don't have a logic analyzer, would a scope work for you? That's what I've been using.

    Thanks

  • Hi,

    Using a logic analyzer would be ideal, but a scope should be able to let me see the UART signals enough to tell if the CC3120 is sending back the ack or not when you deassert nHib.

    Regards,

    Michael

  • Sorry it took a while to respond, I've been caught up in other projects.

    Bellow are the the signals being sent between the F28379D and the CC3120boost. The yellow signal is the Rx line of the CC3120 that I've pulled low, the purple signal is the nHIB pin that gets reset and then a message is sent on the Tx line of the cc3120 (green). The second image is a zoomed in view of the signal sent on the green line.

    Thanks

  • Hi,

    Your trace looks correct to me. For reference, this is what I have captured with my logic analyzer:

    I suggest you take a look at the UART interface of your host device, and ensure that is not simply missing the ACK signal.

    Regards,

    Michael