Exiting SWD mode

[Charles Manning]

I have code that uses two GPIOs to program an NRF51822 via SWD mode. This code all works fine and suceeds in programming the device.

What I would like to do is get the NRF51822 to exit SWD mode, returning the pins to their previous function (eg. RESET).

Is there any way to do that?

[Charles Manning]

I found the answer in the ref manual

Normal mode can always be resumed by performing a "hard-reset" through the SWD interface:

1. Enter debug interface mode.
2. Enable reset through the RESET register in the POWER peripheral.
3. Hold the SWDCLK and SWDIO/nRESET line low for a minimum of 100 μs.

I had misread this to mean that doing any of the above would do it.

You need to do all of these steps in the sequence shown above.