Setting watchpoint on nRF52832DK with GDB

RE: Setting watchpoint on nRF52832DK with GDB

Gordon — Tue, 23 Jan 2018 08:07:28 GMT

thanks! Sorry - I'd expected 'convert to answer' to pull the comment and all comments after it. This is great news - so the WDT gets set by softdevice init, so I could maybe add an #ifdef DEBUG macro in my code that removed it for debug builds - or could just do it in GDB manually.

RE: Setting watchpoint on nRF52832DK with GDB

Håkon Alseth — Tue, 23 Jan 2018 06:54:34 GMT

Hi Gordon! Forgot about this feature on nRF52, but it has the option to pause the WDT when the CPU is halted. This is field C (bit 3) in the NRF_WDT->CONFIG register, and the reset value is '0', so make sure this field is set to '0', and the WDT shouldn't cause any issues when debugging.

RE: Setting watchpoint on nRF52832DK with GDB

Gordon — Mon, 22 Jan 2018 09:11:48 GMT

Hi, thanks - I tried awatch before and it said Expression cannot be implemented with read/access watchpoint.. I've actually just tried this again and found that awatch array[5] and awatch &array[5] fails, but awatch array works, as does awatch *(uint32_t*)0x20003898 so I guess I was just using it wrong - thanks! Interestingly when I use normal watch with the different expressions it says Hardware watchpoint 11 as opposed to Watchpoint 11 when I manually specify the address. Do you have a link for info on disabling the WDT in GDB? That always made things very painful and I assumed it wasn't something I could do anything about.

RE: Setting watchpoint on nRF52832DK with GDB

Håkon Alseth — Mon, 22 Jan 2018 07:50:53 GMT

Good morning Gordon,

Did you try to use awatch <var> instead of watch <var>? I'd recommend to disable the WDT when debugging, as the debugger will halt the CPU, but not any peripherals in the background. This will cause the WDT to reset your system after the bkpt has reached.

Cheers, Håkon