[179] RTC: COMPARE event is generated twice from a single RTC compare match

This anomaly applies to IC Rev. Rev 1, build codes QIAA-Cx0, CKAA-Cx0.

It was inherited from the previous IC revision Engineering C nRF52840.

Symptoms

Tasks connected to RTC COMPARE event through PPI are triggered twice per compare match.

Conditions

RTC registers are being accessed by CPU while RTC is running.

Consequences

Tasks connected to RTC COMPARE event through PPI are triggered more often than expected.

Workaround

Do not access the RTC registers, including the COMPARE event register, from CPU while waiting for the RTC COMPARE event. Note that CPU interrupt from this event can still be enabled.