2.5.1 External Clock/Crystal Status Bit is Not Set When the External Clock Source is Ready

If an external clock source is selected (SELHF in XOSCHFCTRLA is ‘1’) and the Run Standby (RUNSTDBY) bit in XOSCHFCTRLA is ‘1’ without the clock source being requested, the External Clock/Crystal Status (EXTS) bit will not be set to ‘1’ when the external clock source is ready.

Work Around

Request the clock from RTC or TCD before checking the EXTS bit.

Affected Silicon Revisions

Rev. A4 Rev. A5 Rev. B0
X - -