SAM4L Datasheet, PDF (584/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
Figure 24-15. Typical Connection to a RS485 Bus
USART
RXD
TXD
RTS
Differential
Bus
If a timeguard has been configured the RTS pin will remain high for the duration specified in TG,
as shown in Figure 24-16.
Figure 24-16. Example of RTS Drive with Timeguard Enabled
Baud Rate
Clock
TG = 4
TXD
Write
THR
Start
Bit
D0
D1
D2
D3
D4
D5
D6
D7
Parity Stop
Bit Bit
TXRDY
TXEMPTY
RTS
24.6.6
Hardware Handshaking
The USART features an out-of-band hardware handshaking flow control mechanism, imple-
mentable by connecting the RTS and CTS pins with the remote device, as shown in Figure 24-
17.
Figure 24-17. Connection with a Remote Device for Hardware Handshaking
USART
TXD
RXD
CTS
RTS
Remote
Device
RXD
TXD
RTS
CTS
42023C–SAM–02/2013
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