Datasheet

591
SAM9G45 [DATASHEET]
Atmel-6438O-ATARM-SAM9G45-Datasheet_08-Dec-15
Figure 32-22. Parity Error
32.7.3.10 Multidrop Mode
If the PAR field in the Mode Register (US_MR) is programmed to the value 0x6 or 0x07, the USART runs in
Multidrop Mode. This mode differentiates the data characters and the address characters. Data is transmitted with
the parity bit at 0 and addresses are transmitted with the parity bit at 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when the parity bit is high
and the transmitter is able to send a character with the parity bit high when the Control Register is written with the
SENDA bit at 1.
To handle parity error, the PARE bit is cleared when the Control Register is written with the bit RSTSTA at 1.
The transmitter sends an address byte (parity bit set) when SENDA is written to US_CR. In this case, the next byte
written to US_THR is transmitted as an address. Any character written in US_THR without having written the
command SENDA is transmitted normally with the parity at 0.
D0 D1 D2 D3 D4 D5 D6 D7
RXD
Start
Bit
Bad
Parity
Bit
Stop
Bit
Baud Rate
Clock
Write
US_CR
PARE
RXRDY
RSTSTA = 1