Programming nRF51422 externally

[Ehsan]

Hi,

I have designed and made a PCB with the nRF51422 chip on it. I am programming the chip externally using the P20 header pins on the nRF51-DK. I am not sure whether the chip on the PCB is being detected by the DK as the program is being loaded onto the DK chip. Is the chip on the DK also programmed normally when trying to program a chip externally or is the DK chip completely ignored once an external chip is detected? Also, is there a way to check whether the external chip is even being detected (in Keil uVision)?

Regards, Ehsan.

[endnode]

You should be able to test flashing with some simple FW which e.g. starts to blink with LEDs on DK board so if nRF5x chip on the board is erased and then it starts to blink (don't forget to reset the board to be sure it's not halted in debug mode or something similar) then you know you are not targeting external chip through P19 or P20. There are posts which can help with good set-up, see here and here. I personally use the trick with short between PIN2 (VDD) and PIN3 (VTG) on P20, that will make sure that SEGGER J-Link OB will always try to program external target on P20 and not internal chip. You can verify easily that even if you unplug other wires from P20 if you short VDD and VTG nrfjprog (or other flashing program you use) reports error "target not attached" (or something similar;).

[Ehsan]

The debugger seems to be trying to program the external target board but it fails each time. It displays the following error in the build output window: ***JLink Error: Communication timed out: Requested 20 bytes, received 0 bytes ! Could not read hardware status!

What would this suggest? Also, does the GND DETECT pin on P20 provide a GND connection too? Thanks.