SAM4L Datasheet, PDF (570/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
frame lengths with the time-out feature. The USART supports several operating modes, provid-
ing an interface to RS485, LIN, and SPI buses, with ISO7816 T=0 and T=1 smart card slots,
infrared transceivers, and modem port connections. Communication with slow and remote
devices is eased by the timeguard. Duplex multidrop communication is supported by address
and data differentiation through the parity bit. The hardware handshaking feature enables an
out-of-band flow control, automatically managing RTS and CTS pins. The Peripheral DMA Con-
troller connection enables memory transactions, and the USART supports chained buffer
management without processor intervention. Automatic echo, remote-, and local loopback test
modes are also supported.
24.3 Block Diagram
Figure 24-1. USART Block Diagram
Peripheral DMA
Controller
Channel Channel
USART
Interrupt
Controller
USART
Interrupt
Receiver
Transmitter
I/O
Controller
Power
Manager
CLK_USART
CLK_USART/DIV
DIV
Modem
Signals
Control
BaudRate
Generator
User
Interface
Peripheral bus
RXD
RTS
TXD
CTS
DTR
DSR
DCD
RI
CLK
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