nrfjprog ---pinreset not working on nRF52

[AmiguelS]

Hello! I am using a custom board that contains a nRF52832 device. The board has the SWDIO and SWDCK lines connected, which I have successfully been using to flash and debug the firmware.

However, I cannot seem to make the device leave debug mode. I have tried to use the --pinresetenable and --pinreset command with nrfjprog, but with no success.

The procedure I followed was:

• 1. Disconnect and reconnect device battery. Current consumption is bellow 0.1mA, as expected.
• 2. Connect Segger debugger, start JLinkExe and run power on and connect. Current consumption becomes around 2mA. An increase was expected.
• 3. Close JLinkExe.
• 4. Run nrfjprog --pinresetenable -f nrf52. echo $? returns 0.
• 5. Run nrfjprog --pinreset -f nrf52. echo $? returns 0.
• 6. Disconnect debugger from board. Current consumption remains ~2mA

Do any other steps have to be taken to switch back to normal mode? Does the board have to implement anything else other than the SWD lines for these commands to work?

[endnode]

I guess PINRESET needs separate SWD RST wire attached, do you have it? Otherwise use nrfjprog -r -f NRF52 which sends reset command over SWD protocol, just note that this doesn't work if you have locked nRF52 chip (read back protection which disables whole debugging interface).

[AmiguelS]

@endnode There is nothing connected to P0.21/RESET. Should this be connected to nReset? When the pinreset command is issued, the current consumption increases slightly (for about 3 seconds), the Segger LED blinks green a couple of times and blinks red one time. However, the chip does not reset.

nrfjprog -r -f NRF52 does in fact reset the chip, but apparently it doesn't bright it out of debug mode, since the current consumption goes back to where it was (~2mA).

[endnode]

Yes, I believe P0.21/RESET should be connected to SWD nReset wire, but I cannot find in NRFTOOLS docs what is difference between nrfjprog -p and nrfjrpog -r, I only assume...

[AmiguelS]

@endnode I also looked through the documentation and found very little additional info. It says -r performs a soft-reset, and -p performs a pin reset, by pin reset I'm assuming they mean hard reset.

On the schematic of the nRF52 DK, nReset is indeed connected to pin P0.21, as seen on page 4.

[AmiguelS]

@endnode Would pulling the reset pin (P0.21) low be enough to properly reset the device and enter normal mode?