Frame Error on a Previous Message May Cause False Start Bit Detection

A false start bit detection will trigger if receiving a frame with RXDATAH.FERR set and reading the RXDATAL before the RxD line goes high.

Work around

Wait for the RxD pin to go high before reading RXDATA, for instance by polling the bit in PORTn.IN where the RxD pin is located.

Affected Silicon Revisions

ATtiny416
Rev. A Rev. B            
X X            
ATtiny816
Rev. A Rev. B            
X X