Is calling NVIC_SystemReset() enough after flashing?

[Marius Heil]

Hello,

is it enough to call NVIC_SystemReset() after I flashed a board so that it returns to lower power consumption? Or do I have to pull out the battery?

Marius

[Ole Bauck]

EDIT 22.02.2017: Added pin reset as a option for getting nRF52 out of debug mode.

You will not get out of debug mode with NVIC_SystemReset(). See below for how to get out of debug mode for nRF51 and nRF52.

nRF51: See part 11.1.3 "Resuming normal mode" in the Reference Manual. You can do a pin reset with nrfjprog: nrfjprog --pinreset.

nRF52: Pin reset (if enabled), power on reset (POR) and brown-out reset (BOR) will get the chip out of debug mode.

Note: If you use jlink version between 6.10b (might also be earlier versions, have not checked) and 6.12e, the debugger will not get the device out of debug mode after programming. Latest version at the moment is 6.12j, which seems to work well.

[Ole Bauck]

Hi, I was wrong that BOR and POR is the only ways to get the device out of debug mode, you can also use pin reset. I have updated the answer.

The nRF52 requires more pulses on the SWDCLK than nRF51 and some words written to enter debug mode, so the nRF52 is not prone to go into debug mode if there is noise on the SWDCLK pin as the nRF51 was.