I can read "NRF_POWER->RESETREAS" in code, but I can't with nrfjprog

[Jeong Hyun Seok]

I put my code before ble_stack_init()

reset_reason = NRF_POWER->RESETREAS;
NRF_LOG_PRINTF("reset_reason: 0x%08x.\n",reset_reason );
//NRF_POWER->RESETREAS = 0xffffffff;

and it works

but when I tried nrfjprog, it did not work.

nrfjprog --memrd 0x40000400 --n 4

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I mean first method, I get 0x00000002 (=watchdog reset) second method, I get 0x00000000

Why this happend?

[Susheel Nuguru]

That is because you are explicitly clearing the register in your program after you printed it.

NRF_POWER->RESETREAS = 0xffffffff;

This will clear the register before you get a chance to read from nrfjprog. Comment this out and you will read the same in both.

[Jeong Hyun Seok]

Sorry for confusion. But I actually did not used that line while I tested

so my test was like this

reset_reason = NRF_POWER->RESETREAS;
NRF_LOG_PRINTF("reset_reason: 0x%08x.\n",reset_reason );
//NRF_POWER->RESETREAS = 0xffffffff;

[Susheel Nuguru]

I am pretty sure that some part of your code is clearing the register. Can you please upload your test code and tell me the laser marking of the chip so that i can test it on my desk.

[Jeong Hyun Seok]

You are right! Why I did not think of breakpoint? I checked Power Register in keil and checked when register value change.

• My colleague put clear code below somewhere.

Thank you. it helped a lot. :-)