AT32F421
Series Reference Manual
2022.11.11
Page 134
Rev 2.02
Figure 12-4 IrDA DATA(3/16)
– normal mode
Normal frame
1
Start
bit
0
1
0
1
1
0
0
Stop
bit
TX pin
RX pin
3/16
4.
Hardware flow control mode:
RTS and CTS flow control can be enabled by setting RTSEN=1 and CTSEN=1, respectively. This is
to control serial data flow between two devices.
RTS: the RTS becomes active (pull-down means low) as soon as the USART receiver is ready to
receive a data. When the data has arrived (starts at each STOP bit) in the receive register, the RTS
bit is set, indicating request to stop data transfer at the end of current frame.
CTS: the USART transmitter checks the CTS input before sending next frame. The next data is sent
if CTS is active (when low); if CTS becomes inactive (when high) during transmission, it stops
sending at the end of current transfer.
Figure 12-5 Hardware flow control
RX pin
RTS
frame0
frame1
RTS follow control
:
CTS
TX pin
frame0
frame1
CTS follow control
:
frame2
5.
Mute mode:
Silent mode can be entered by setting RM=1. It is possible to wake up from silent mode by setting
WUM=1 (ID match) and WUM=0 (idle line), respectively. The ID[3: 0] is configurable. When ID match
is selected, if the MSB of data bit is set to 1, it indicates that the current data is ID, and the four LSB
represent ID value.