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CC8531: Can only flash device once

Mattias Dabo
Prodigy 10 points
Part Number: CC8531

I'm wondering if anyone else have stumbled on the same issue that I have with programming the CC85xx devices?
I'm using the CC Debugger and PurePath Wireless Console and for the moment only CC8531.

So far I've built 4 boards and all were detected by both the CC Debugger and PPWC. Flashing the chip appears to be successful and the status LED on the CC8531 board is flashing indicating "alone mode", but then none of the boards can be flashed again. CC Debugger does at this stage detect the connected CC8531 (green LED) but in PPWC it stays as disconnected.

I have tried with and without a 56k pull-up resistor on the reset pin but that makes no difference either way.

Any ideas would be greatly appreciated

Thanks,

Mattias

Before 1st flash

After 1st flash

Reconnecting

CC85xxEvalBoard_vers5c.pdf

  • 0
    Prodigy 10 points

    I'm starting to believe my CC Debugger is buggered. I measured the voltage on the reset pin and it stays high at all times.

    Is one to expect the reset pin go low when pressing the reset button on the CC Debugger?

  • 0 in reply to Mattias Dabo
    TI__Genius 10580 points

    Mattias,

    Do you have another CC Debugger you can test with? Do you see the same behavior using the CC85xx evaluation kit, or is it limited to your custom hardware?

    Regards,

    Daniel

  • 0 in reply to daniel_o
    Prodigy 10 points

    Thanks Daniel for your reply. 

    I have no evaluation kit. They do not even seem to be available from anywhere. 
    Our design originating from the reference design. The 4 layer (L1=signal, L2=GND, L3=power, L4=signal) board is tiny measuring 25mm x 57mm and consists of 0402 components through out. Traces are very short due to the size of the board. We have also paid extra attention to ensure a good signal integrity using via stitching around clock signals, X7R decoupling capacitors etc.

    I've come to realise that the crystal need to be working in fundamental mode. They are quite difficult to source at the moment, but I'm working to source some.

    After a closer inspection, it's clear the the CC Debugger we have is of a very early model with only two SN74AVC4T245PWs on the rear side of the PCB, compared with four dito on newer boards. Along with many other changes.
    So I went ahead and ordered a new CC Debugger.

    However, I'm still a bit perplex as to why we could only flash the boards first time but not again!

    Thanks,

    Mattias

  • 0 in reply to Mattias Dabo
    TI__Genius 10580 points

    Mattias,

    I'm not sure exactly why the older CC Debugger is causing the issues, but it would be that the debugger isn't holding the device in reset properly once it's running or something similar to that. Please let me know if the new CC Debugger solves your issues.

    Regards,

    Daniel

  • 0 in reply to daniel_o
    Prodigy 10 points

    The new debugger arrived. Although it's obvious that it is not an original (it was cheap from Amazon so not surprised), the PCB layout corresponds with TI's documentation. And the good news is that it works as expected. The new one on the right

    Pairing the boards does not work however. But after doing some research, I'm now fairly convinced that it's due to the crystal not operating in fundamental mode. I've got some coming in soon to test with.

    Thanks,

    Mattias

  • 0 in reply to Mattias Dabo
    TI__Genius 10580 points

    Glad the new debugger is working! Feel free to start a new thread if you need more assistance.