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AT32F435/437
Series Reference Manual
2022.11.11
Page 215
Rev 2.03
Figure
12-5
USART interrupt map diagram
USART
interrupt
TDBE
TDBEIEN
TDC
TDCIEN
CTSCF
CTSCFIEN
IDLEF
IDLEIEN
RDBFIEN
ROERR
RDBFIEN
RDBF
PERR
PERRIEN
BFF
BFIEN
FERR
NERR
ROERR
ERRIEN
DMAREN
12.11 I/O pin control
The following five interfaces are used for USART communication.
RX: Serial data input.
TX: Serial data output. In single-wire half-duplex and Smartcard mode, the TX pin is used as an I/O for
data transmission and reception.
CK: Transmitter clock output. The output CLK phase, polarity and frequency can be programmable.
CTS: Transmitter input. Send enable signal in hardware flow control mode.
RTS: Receiver output. Send request signal in hardware flow control mode.
12.12 USART registers
These peripheral registers must be accessed by words (32 bits).
Table 12-5 USART register m ap and reset value
Register
Offset
Reset value
USART_STS
0x00
0x0000 00C0
USART_DT
0x04
0x0000 0000
USART_BAUDR
0x08
0x0000 0000
USART_CTRL1
0x0C
0x0000 0000
USART_CTRL2
0x10
0x0000 0000
USART_CTRL3
0x14
0x0000 0000
USART_GTP
0x18
0x0000 0000
12.12.1 Status register (USART_STS)
Bit
Register
Reset value
Type
Description
Bit 31: 10 Reserved
0x000000
resd
Forced 0 by hardware.
Bit 9
CTSCF
0x0
rw0c
CTS change flag
This bit is set by hardware when the CTS status line
changes. It is cleared by software.
0: No change on the CTS status line
1: A change occurs on the CTS status line.
Bit 8
BFF
0x0
rw0c
Brake frame flag
This bit is set by hardware when a brake frame is
detected. It is cleared by software.
0: Brake frame is not detected.