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How to use UART in the nRF51822 Bluetooth Smart Beacon Kit?

The nRF51822 Bluetooth Smart Beacon Kit has P0.09 and P0.11 connected to the programming connector P2 (Pin 3 and Pin 6). From the User Guide:

Programming Connector P2

Can I use them as UART through the J-LINK debugger (but I probably can't since I see that nRESET and SWO are supposed to be there) or I have to use an intermediary PCB with FTDI? If so I assume that I can't debug and use UART at the same time (or maybe I can disable nRESET and SWO on the debugger)?

Thank you very much!

  • You can probably use both at the same time but that would require to route each of these pins on Beacon's special programming header to different PIN on debugger (whatever it is) and UART/serial convertor (again whatever it is). Then you can use nRF5x DK (and rote SWD PINs to P20 or P19 while UART Tx/Rx PINs P011 and P0.09 to respective UART PINs on your DK - to have it all working you need to erase or otherwise disable internal nRF5x target on DK board first!) for JTAG/SWD and UART simultaneously or split it and use some board for debugging/flashing (can be nRF5x DK with SEGGER J-Link OB) and another board for UART/serial input to your machine (again it could be nRF DK which emulates virtual COM port thanks to SEGGER J-Link OB FW or it can be stand-alone FTDI "serial to USB" convertor or anything similar).

    So it's question what is more time consuming and costly for you: split the wiring on Beacon's pins to several boards or split it and then connect to single board.

  • (e.g. if you have Tag Connect 6-pin needle connector with 10-pin or other header on the other side of ribbon cable then you might use certain 10-pin interconnect or conversion boards and through some jumpers and breadboards achieve what you need. It worked for me, just make sure you use well isolated wires and that you keep them as short and as equal length as possible because SWD can be sensitive to noise).

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