STM8S datasheet(368/467 Pages) STMICROELECTRONICS

368 / 467 page

Universal asynchronous receiver transmitter (UART)

RM0016

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DocID14587 Rev 14

Bit 3 TEN: Transmitter enable (1) (2)

This bit enables the transmitter. It is set and cleared by software.

0: Transmitter is disabled

1: Transmitter is enabled

Bit 2 REN: Receiver enable

This bit enables the receiver. It is set and cleared by software.

0: Receiver is disabled

1: Receiver is enabled and begins searching for a start bit

Bit 1 RWU: Receiver wakeup

–UART mode

This bit determines if the UART is in mute mode or not. It is set and cleared by software and can be

cleared by hardware when a wakeup sequence is recognized.(3) (4)

– LIN slave mode (UART2, UART3 and UART4 only, if bits LINE and LSLV are set)

While LIN is used in slave mode, setting the RWU bit allows the detection of Headers only and

prevents the reception of any other characters. Refer to Mute mode and errors on page 355. In LIN

slave mode, when RXNE is set, the software can not set or clear the RWU bit.

0: Receiver in active mode

1: Receiver in mute mode

Bit 0 SBK: Send break

This bit set is used to send break characters. It can be set and cleared by software.It should be set

by software, and will be reset by hardware during the stop bit of break.

0: No break character is transmitted

1: Break character will be transmitted

1. During transmission, a “0” pulse on the TEN bit (“0” followed by “1”) sends a preamble (idle line) after the current word.

2. When TEN is set there is a 1 bit-time delay before the transmission starts.

3. Before selecting Mute mode (by setting the RWU bit) the UART must first receive a data byte, otherwise it cannot function

in Mute mode with wakeup by Idle line detection.

4. In Address Mark Detection wakeup configuration (WAKE bit=1) the RWU bit cannot be modified by software while the

RXNE bit is set.

STM8S Datasheet(PDF) 368 Page - STMicroelectronics