16.5.2.5 Clock Ready Flag

There is a slight delay between writing to CPUDIV until the new clock settings become effective.

During this interval, the Clock Ready flag in the Interrupt Flag Status and Clear register (INTFLAG.CKRDY) will return zero when read. If CKRDY in the INTENSET register is set to '1', the Clock Ready interrupt will be triggered when the new clock setting is effective. The new CPUDIV value must not be re-written while INTFLAG.CKRDY reads '0'. The system may become unstable or hang, and a violation is reported to the PAC module.