Hi, As has been mentioned many times, the DIF on both the nRF51 and nRF52 consumes quite a bit of current. In the past, on the nRF51, I've relied on power cycling both chipsets to reset the DIF, as I could get no debugger command to ever do this correctly.
I was hoping that this behavior would be corrected on the nRF52. I'm currently designing an application where the entirety of the device (battery, etc.) is fully encapsulated for a one-time-use application. Only a SWD interface (including !RESET) for reprogramming and testing in application is exposed. It's also used as a backup interface to read out some stored readings should the internal battery lose power.
Now, if the SWD interface ever accidentally gets enabled (I believe this was possible depending on noise on the nRF51), or if debug mode needs to be entered to read out stored readings, the chip will get stuck on the DIF.
Is there any known way to reset the DIF to reduce power consumption after a debug session through the interface or in software without a power cycle?
I have tried many recommendations on the forum to no avail. This includes a pin reset (both using a J-link and by manually shorting the reset pin). I've also verified that PSELRESET is configured appropriately. In fact, I can see the current consumption fall from ~3mA down to ~800uA for maybe half a second after RESET is held low, indicating that it is configured appropriately. After that, it just jumps to the normal current with DIF on.
All of the other components on the board have been accounted for - after power-on, without any DIF usage, the entirety of the board consumes 9uA, most of which comes from a separate component. The nRF52 consumes about ~1uA.
Any solutions? Perhaps there's some debugger command or internal DIF register that needs to be written? Or will I simply need to design hardware to power cycle the nRF52?