I cannot reset the nRF52 DK while running on battery power. I've tried multiple examples of the SDK which didn't work. However, when connecting the DK via USB, the reset works just fine. On a second board, the nRF52840 DK the reset button works for battery and USB powering, so I assume it should work on the nRF52 DK for both options as well. Is it possible to reset the nRF52 DK while running on battery power? If so, how can I enable the reset function?
The reset button is connected to both the debugger and the reset pin on the nRF52840 by default, so there is no HW change needed. However, the default state of the nRF52840 chip is that pin reset is disabled. When connected to USB power the debugger ie enabled and will reset the device via SWD, so the reset button works in that case even without pin reset enabled.
To make pin reset work, you need to write to the persistent PSELRESET registers in the UICR. The simplest way to do this is by using "nrfjprog.exe --pinresetenable".
thank you for the help. Does this hold true for the nRF52832 chip as well? This is the chip used on the nRF52 DK.
TobiasM said:Does this hold true for the nRF52832 chip as well?
Yes, pin reset is disabled by default (after a full flash erases) on all nRF52xxx devices.
I've tried your suggested command and it states "Enabling pin reset." but I'm still not able to reset the board. Could you describe in detail how the more complicated way would look like?
You are right. I read your original question too quickly and replied for the nRF52840 DK. The nRF52 DK (with nRF52832) does not have the reset button connected to the reset pin (P0.21) on the nRF. You can short SB17 to get the reset pin out on a pin header to make it easy to hook up a button or a jumper wire, though.