Datasheet
Writing '1' to CTRLB.RXEN when the USART is enabled will set SYNCBUSY.CTRLB, which will remain
set until the receiver is enabled, and CTRLB.RXEN will read back as '1'.
This bit is not enable-protected.
Value Description
0
The receiver is disabled or being enabled.
1
The receiver is enabled or will be enabled when the USART is enabled.
Bit 16 – TXEN Transmitter Enable
Writing '0' to this bit will disable the USART transmitter. Disabling the transmitter will not become effective
until ongoing and pending transmissions are completed.
Writing '1' to CTRLB.TXEN when the USART is disabled will set CTRLB.TXEN immediately. When the
USART is enabled, CTRLB.TXEN will be cleared, and SYNCBUSY.CTRLB will be set and remain set until
the transmitter is enabled. When the transmitter is enabled, CTRLB.TXEN will read back as '1'.
Writing '1' to CTRLB.TXEN when the USART is enabled will set SYNCBUSY.CTRLB, which will remain
set until the transmitter is enabled, and CTRLB.TXEN will read back as '1'.
This bit is not enable-protected.
Value Description
0
The transmitter is disabled or being enabled.
1
The transmitter is enabled or will be enabled when the USART is enabled.
Bit 13 – PMODE Parity Mode
This bit selects the type of parity used when parity is enabled (CTRLA.FORM is '1'). The transmitter will
automatically generate and send the parity of the transmitted data bits within each frame. The receiver
will generate a parity value for the incoming data and parity bit, compare it to the parity mode and, if a
mismatch is detected, STATUS.PERR will be set.
This bit is not synchronized.
Value Description
0
Even parity.
1
Odd parity.
Bit 10 – ENC Encoding Format
This bit selects the data encoding format.
This bit is not synchronized.
Value Description
0
Data is not encoded.
1
Data is IrDA encoded.
Bit 9 – SFDE Start of Frame Detection Enable
This bit controls whether the start-of-frame detector will wake up the device when a start bit is detected
on the RxD line.
This bit is not synchronized.
SAM D21 Family
SERCOM USART
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 492