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AWR1843BOOST: are the UART pull up resistors necessary?

Jairo Gallardo
Expert 1640 points
Part Number: AWR1843BOOST
Other Parts Discussed in Thread: AWR1843, UNIFLASH

Hi, in the schematic I can see two 100k resistors as pull ups in the UART lines, why are necessary, for the boards to be placed in the J6 connector or for the TM4C1294NCPDTT3??

  • 0
    Expert 1640 points

    We have a custom awr1843 board and we are flashing the board using an USB - UART cable connected to rs232 pins and sometimes the COM port is not recognized or the flashing process fails and we have not included any pull up, thanks

  • 0
    Expert 1640 points

    in this post says:

    "Care must be taken some of the USB to UART may not reproduce escape character, then Uniflash tool may not understand properly."

    and in this post you recommended me this usb-uart tool, are sure that this tool is compatible with uniflash and does not have the limitation of the escape character?, thanks

  • 0 in reply to Jairo Gallardo
    TI__Mastermind 30055 points

    Hello Jairo,

    I have used that same USB to UART cable many times for flashing and I have not encountered any issues. It is possible that the missing pullup resistors is causing the failure, the pullups are required for the UART interface. Can you try soldering some pullup resistors on your board and see if the issue resolves? It doesnt have to be 100k, anything over 10k should be fine. 

    Regards,

    Adrian