Datasheet

Figure 46-25. Break Transmission
D0 D1 D2 D3 D4 D5 D6 D7
TXD
Start
Bit
Parity
Bit
Stop
Bit
Baud Rate
Clock
Write
US_CR
TXRDY
TXEMPTY
STPBRK = 1
STTBRK = 1
Break Transmission End of Break
46.6.3.14 Receive Break
The receiver detects a break condition when all data, parity and stop bits are low. This corresponds to detecting a
framing error with data to 0x00, but FRAME remains low
.
When the low stop bit is detected, the receiver asserts US_CSR.RXBRK. This bit may be cleared by writing a ‘1’ to
US_CR.RSTSTA.
An end of receive break is detected by a high level for at least 2/16 of a bit period in Asynchronous operating mode or
one sample at high level in Synchronous operating mode. The end of break detection also asserts US_CSR.RXBRK
bit.
46.6.3.15 Hardware Handshaking
The USART features a hardware handshaking out-of-band flow control. The RTS and CTS pins are used to connect
with the remote device, as shown in the following figure.
Figure 46-26. Connection with a Remote Device for Hardware Handshaking
USART
TXD
CTS
Remote
Device
RXD
TXDRXD
RTS
RTS
CTS
Setting the USART to operate with hardware handshaking is performed by writing the value 0x2 to
US_MR.USAR
T_MODE.
When hardware handshaking is enabled, the USART displays similar behavior as in standard Synchronous or
Asynchronous modes, with the difference that the receiver drives the RTS pin and the level on the CTS pin modifies
the behavior of the transmitter, as shown in the following figures. The transmitter can handle hardware handshaking
in any case.
Figure 46-27. RTS Line Software Control when US_MR.USART_MODE = 2
RTS
Write
US_CR.RTSDIS
RXD
Write
US_CR.RTSEN
The following figure shows how the transmitter operates if hardware handshaking is enabled. The CTS pin disables
the transmitter
. If a character is being processed, the transmitter is disabled only after the completion of the current
character and transmission of the next character occurs as soon as the pin CTS falls.
SAM E70/S70/V70/V71 Family
Universal Synchronous Asynchronous Receiver T
ransc...
© 2019 Microchip T
echnology Inc.
Datasheet
DS60001527D-page 1198