DocID018909 Rev 11
959/1731
RM0090
Universal synchronous asynchronous receiver transmitter (USART)
1010
•
Transfer detection flags:
–
Receive buffer full
–
Transmit buffer empty
–
End of transmission flags
•
Parity control:
–
Transmits parity bit
–
Checks parity of received data byte
•
Four error detection flags:
–
Overrun error
–
Noise detection
–
Frame error
–
Parity error
•
Ten interrupt sources with flags:
–
CTS changes
–
LIN break detection
–
Transmit data register empty
–
Transmission complete
–
Receive data register full
–
Idle line received
–
Overrun error
–
Framing error
–
Noise error
–
Parity error
•
Multiprocessor communication - enter into mute mode if address match does not occur
•
Wake up from mute mode (by idle line detection or address mark detection)
•
Two receiver wakeup modes: Address bit (MSB, 9
th
bit), Idle line
30.3
USART functional description
The interface is externally connected to another device by three pins (see
). Any
USART bidirectional communication requires a minimum of two pins: Receive Data In (RX)
and Transmit Data Out (TX):
RX: Receive Data Input is the serial data input. Oversampling techniques are used for data
recovery by discriminating between valid incoming data and noise.
TX:
Transmit Data Output. When the transmitter is disabled, the output pin returns to its I/O
port configuration. When the transmitter is enabled and nothing is to be transmitted, the TX
pin is at high level. In single-wire and smartcard modes, this I/O is used to transmit and
receive the data (at USART level, data are then received on SW_RX).