Errata nRF52840 - System: Bits in RESETREAS are set when they should not be

This anomaly applies to IC Rev. Engineering A, build codes QIAA-AA0.

Symptoms

After pin reset, RESETREAS bits other than RESETPIN might also be set.

A pin reset has triggered.

If the firmware evaluates RESETREAS, it might take the wrong action.

When RESETREAS shows a pin reset (RESETPIN), ignore other reset reason bits.

Important: RESETREAS bits must be cleared between resets.

Apply the following code after any reset:

 
if (NRF_POWER->RESETREAS & POWER_RESETREAS_RESETPIN_Msk){
    NRF_POWER->RESETREAS =  ~POWER_RESETREAS_RESETPIN_Msk;
}

This workaround is implemented in MDK version 8.13.0 and later.