24.3.2.4.1 Receiver Error Flags
The USART receiver features error detection mechanisms that uncover corruption
of the transmission. These mechanisms include the following:
- Frame Error detection - controls whether the received frame is valid
- Buffer Overflow detection - indicates data loss due to the receiver buffer being full and overwritten by the new data
- Parity Error detection - checks the validity of the incoming frame by calculating its parity and comparing it to the Parity bit
Each error detection mechanism controls
one error flag that can be read in the RXDATAH register:
- Frame Error (FERR)
- Buffer Overflow (BUFOVF)
- Parity Error (PERR)
Note: If the Character Size bit field (the
CHSIZE bits in the USARTn.CTRLC register) is set to nine bits, low byte first (9BITL), the
RXDATAH register will, instead of the RXDATAL register, trigger the RX buffer to shift out
the RXDATA bytes. The RXDATAL register must, in that case, be read before the RXDATAH
register.