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Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Figure 23-12 Mute mode using idle line detection
Address mark detection
By configuring the USART_CTRL1.WUM bit to 1, the USART performs address mark detection. The address of the
receiver is programmable through the USART_CTRL2.ADDR[3:0] bits. If the MSB is 1, the byte is considered an
address, otherwise it is considered data.
In this mode, the USART can enter mute mode by:
When the receiver does not contain data, USART_CTRL1.RCVWU can be written to 1 by software, and USART
enters mute mode;
Note: When the receive buffer contains no data (RXNE=0 in USART_SR), the USART_CTRL1.RCVWU bit can
be written to 0 or 1. Otherwise, the write operation is ignored.
When the received address does not match the address of the USART_CTRL2.ADDR[3:0] bits,
USART_CTRL1.RCVWU is written to 1 by hardware.
In mute mode, none of the receive status bits are set and all receive interrupts are disabled.
When the received address matches the address of the USART_CTRL2.ADDR[3:0] bits, the USART is woken up
and USART_CTRL1.RCVWU is cleared. The USART_STS.RXDNE bit will be set when this matching address is
received. Data can then be transmitted normally.
RX
RCVWU
RCVWU written to 1
Mute Mode
Normal Mode
Data1
Data2
Data3
Data4
IDLE
Data5
Data6
Idle frame detected
RXDNE = 1
RXDNE = 1