[201] CLOCK: EVENTS_HFCLKSTARTED might be generated twice

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

EVENTS_HFCLKSTARTED might occur twice, and HFCLKSTAT might be wrong.

Conditions

When running HFCLK with crystal.

Consequences

HFCLKSTAT might be wrong when reading it after HFCLK is started.

Workaround

Disregard HFCLKSTAT and EVENT_HFCLKSTARTED after first EVENT_HFCLKSTARTED.

This workaround is included in nRF5 SDK v15.0.0 and SoftDevices S140, S132, and S112 v6.0.0.