Is there a way to know if debug mode is enabled?

RE: Is there a way to know if debug mode is enabled?

RK — Wed, 13 Apr 2016 05:18:52 GMT

Yes it's documented - look at section 11.1.3 "Resuming normal mode" in the nRF51 series reference manual.

RE: Is there a way to know if debug mode is enabled?

Sébastien Despont — Wed, 13 Apr 2016 05:16:05 GMT

Thank you for your answer. Is this reset sequence documented? I found this thread : NRF_POWER->RESET register (at 0x40000544) to enable pin reset while in debug mode, and then toggle the reset pin.

Is it the suggestion you have written in your answer?

RE: Is there a way to know if debug mode is enabled?

Wojtek — Wed, 13 Apr 2016 01:35:37 GMT

Ah right, i forgot about nrf52. Thanks for explanation!

RE: Is there a way to know if debug mode is enabled?

RK — Wed, 13 Apr 2016 01:33:10 GMT

The person in that thread uses the nRF52, recently at least, so I'm pretty sure that solution is M4 only, not M0.

RE: Is there a way to know if debug mode is enabled?

Wojtek — Wed, 13 Apr 2016 01:30:54 GMT

Yes, I was bit confused because i could not find information about it's implementation in M0. However I though that might work because in the linked thread OP marked this as a solution. Didn't check that myself though.

RE: Is there a way to know if debug mode is enabled?

RK — Wed, 13 Apr 2016 01:18:16 GMT

That's not defined for the Cortex M0 and the OP stated nrf51. On the M0, memory mapping of the debug registers is Implementation Defined and as far as I know, the nrf51 implementation doesn't map them. If it did you could use bit 0 of DHCSR to tell if debug is enbled.

RE: Is there a way to know if debug mode is enabled?

Wojtek — Wed, 13 Apr 2016 00:58:05 GMT

This may be helpful.

RE: Is there a way to know if debug mode is enabled?

RK — Wed, 13 Apr 2016 00:28:31 GMT

The debug registers in the Cortex M0 are only accessible over the DAP port, not via memory reads, so you can't tell if the processor is in debug mode from code.

The nrf51 does have a reset sequence which disables debug mode, can you use that? You set the reset flag in the power register and then have your debugger hold the SWDCLK and SWDIO lines low to hard reset the chip. As long as the debugger doesn't re-connect, you're now reset and not in debug mode.