nrf52832 How-to measure SWDIO / SWDCLK interal pull-up/pull-down?

[florian.gaertner]

We faced the issue that some of our NRF52832 Raytac modules (MDBT42Q-512KV2) don't respond over the SWD interface. But all of these modules were working previously and we were able to flash them.

Is there a possibility to check the SWDIO / SWDCLK pins? E.g. measure the pull-up / pull-down resistance to check if there is an ESD problem?

[Kenneth]

I am not aware of any specific that can cause this to fail, but things to try:

1- Try a different SEGGER programmer, and make sure that VDD is within the the range of the programmer

2. Uninstall the nRF Command lines tools you may have installed, and download the latest. Update the SEGGER firmware if asked

3. Strap nRF52 reset pin to VDD in case it's been by accident enabled

4. Try from a different PC

5. Run the 'nrfjprog --recover' or 'nrfjprog --eraseall'

6. Check the schematic is correct, and that all components are properly mounted.

There is a possibility the nRF52 have been damaged somehow by EOS/ESD, but that is very rare I would say.