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CC3220SF-LAUNCHXL: CC3220SF-LAUNCH pad : how to use external UART ?

v01d
Expert 2035 points
Part Number: CC3220SF-LAUNCHXL

I'm trying to route CC3220 UART to that 20-pin connector, and use with external connection to PC.

Reading this launchpad guide,  per 2.5.7 I switched the jumpers, but , I cannot get anything through that connector - using the RX, TX lines.

Also, it seems the default app, pre-programmed , does not operate / start-up normally if those mentioned jumpers, are switched from Virtual COM to the 20-pin header. 

.. Why?  Any help whats missing?

  • 0
    Guru 39650 points

    Hi,

    This behaviour is expected in case you are using default SOP mode 0-1-0 (2-1-0). In this mode is bootlaoder mode started by state of RX line after reset. By switching to 20-pin connector is state of RX pin not defined (is at low state) and devices goes into boorloader mode.

    You have two options:

    • use SOP mode 0-0-0 for when you need to execute code
    • add weak pull-up to RX line (let say 10k to +3.3V)

    Jan

  • 0 in reply to Hnz
    Expert 2035 points

    Hi Jan,

    Yes, thank you on the SOP, that explains it. I've found the Functional Configurations table for SOP now.

    But, still nothing comes up on the serial that I connect to those UART pins (unless they not in UART mode by default/default app .. ?).  Device , or the app verified running by it blinking leds as before, per that demo app.

    Missing something else on that UART usage ..  

    EDIT:  Aha, it goes to p55 & p57, got it.