Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
774
configuration of the USART. Because there are two bits to 1, 1 bit is added when a parity is odd, or 0 is added
when a parity is even.
When the receiver detects a parity error, it sets the PARE (Parity Error) bit in the US_CSR. The PARE bit can be
cleared by writing the US_CR with the RSTSTA bit to 1.
illustrates the parity bit status setting and
clearing.
Figure 36-22. Parity Error
36.7.3.9 Multidrop Mode
If the value 0x6 or 0x07 is written to the PAR field in the US_MR, the USART runs in multidrop mode. This mode
differentiates the data characters and the address characters. Data is transmitted with the parity bit to 0 and
addresses are transmitted with the parity bit to 1.
If the USART is configured in multidrop mode, the receiver sets the PARE parity error bit when the parity bit is high
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 a one is written to the SENTA bit in the
US_CR.
To handle parity error, the PARE bit is cleared when a one is written to the RSTSTA bit in the US_CR.
The transmitter sends an address byte (parity bit set) when SENDA is written to in the US_CR. In this case, the
To handle parity error, the PARE bit is cleared when a one is written to the RSTSTA bit in the US_CR.
The transmitter sends an address byte (parity bit set) when SENDA is written to in the US_CR. In this case, the
next byte written to the US_THR is transmitted as an address. Any character written in the US_THR without having
written the command SENDA is transmitted normally with the parity to 0.
36.7.3.10Transmitter Timeguard
The timeguard feature enables the USART interface with slow remote devices.
The timeguard function enables the transmitter to insert an idle state on the TXD line between two characters. This
The timeguard function enables the transmitter to insert an idle state on the TXD line between two characters. This
idle state actually acts as a long stop bit.
Table 36-9.
Parity Bit Examples
Character
Hexadecimal
Binary
Parity Bit
Parity Mode
A
0x41
0100 0001
1
Odd
A
0x41
0100 0001
0
Even
A
0x41
0100 0001
1
Mark
A
0x41
0100 0001
0
Space
A
0x41
0100 0001
None
None
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
Parity Error
Detect
Time
Flags
Report
Time