[36] CLOCK: Some registers are not reset when expected

This anomaly applies to IC Rev. Engineering C, build codes QFAA-BB0, CHAA-BA0, CIAA-BA0.

It was inherited from the previous IC revision Engineering B.

Symptoms

After watchdog timeout reset, CPU lockup reset, soft reset, or pin reset, the following CLOCK peripheral registers are not reset:
  • CLOCK->EVENTS_DONE
  • CLOCK->EVENTS_CTTO
  • CLOCK->CTIV

Conditions

After watchdog timeout reset, CPU Lockup reset, soft reset, and pin reset.

Consequences

Register reset values might be incorrect. It may cause undesired interrupts in case of enabling interrupts without clearing the DONE or CTTO events.

Workaround

Clear affected registers after reset. This workaround has already been added into system_nrf52.c file. This workaround has already been added into system_nrf52840.c file present in MDK 8.11.0 or later.