XR21V1412
4
2-CH FULL-SPEED USB UART
REV. 1.3.0
PIN DESCRIPTIONS
NAME
32-QFN
PIN #
TYPE
DESCRIPTION
UART Channel A Signals
RXA
6
I
UART Channel A Receive Data or IR Receive Data. This pin has an internal pull-up
resistor. Internal pull-up resistor is not disabled during suspend mode.
TXA
5
O
UART Channel A Transmit Data or IR Transmit Data.
GPIOA0/RIA#/
RWKA#
12
I/O
UART Channel A general purpose I/O or UART Ring-Indicator input (active low) or
Remote Wakeup Input (
See ”Section 1.5.13, Remote Wakeup” on
page 13.). This pin has an internal pull-up resistor which is disabled during suspend
mode. If using this GPIO as an input, an external pull-up resistor is required to mini-
mize the power consumption in the suspend mode.
GPIOA1/CDA#
11
I/O
UART Channel A general purpose I/O or UART Carrier-Detect input (active low).
This pin has an internal pull-up resistor which is disabled during suspend mode. If
using this GPIO as an input, an external pull-up resistor is required to minimize the
power consumption in the suspend mode.
GPIOA2/DSRA#
10
I/O
UART Channel A general purpose I/O or UART Data-Set-Ready input (active low).
See ”Section 1.5.6, Automatic DTR/DSR Hardware Flow Control” on
page 11. This pin has an internal pull-up resistor which is disabled during suspend
mode. If using this GPIO as an input, an external pull-up resistor is required to mini-
mize the power consumption in the suspend mode.
GPIOA3/DTRA#
9
I/O
UART Channel A general purpose I/O or UART Data-Terminal-Ready output (active
low).
See ”Section 1.5.6, Automatic DTR/DSR Hardware Flow Control”
on page 11. This pin has an internal pull-up resistor which is disabled during sus-
pend mode. If using this GPIO as an input, an external pull-up resistor is required to
minimize the power consumption in the suspend mode.
GPIOA4/CTSA#
8
I/O
UART Channel A general purpose I/O or UART Clear-to-Send input (active low).
See ”Section 1.5.5, Automatic RTS/CTS Hardware Flow Control” on
page 11. This pin has an internal pull-up resistor which is disabled during suspend
mode. If using this GPIO as an input, an external pull-up resistor is required to mini-
mize the power consumption in the suspend mode.
GPIOA5/RTSA#/
RS485A
7
I/O
UART Channel A general purpose I/O or UART Request-to-Send output (active low)
or auto RS-485 half-duplex control.
See ”Section 1.5.5, Automatic RTS/CTS
Hardware Flow Control” on page 11. This pin has an internal pull-up resistor
which is disabled during suspend mode. If using this GPIO as an input, an external
pull-up resistor is required to minimize the power consumption in the suspend mode.
UART Channel B Signals
RXB
16
I
UART Channel B Receive Data or IR Receive Data. This pin has an internal pull-up
resistor. Internal pull-up resistor is not disabled during suspend mode.
TXB
15
O
UART Channel B Transmit Data or IR Transmit Data.
GPIOB0/RIB#/
RWKB#
22
I/O
UART Channel B general purpose I/O or UART Ring-Indicator input (active low) or
Remote Wakeup Input (
See ”Section 1.5.13, Remote Wakeup” on
page 13.). This pin has an internal pull-up resistor which is disabled during suspend
mode. If using this GPIO as an input, an external pull-up resistor is required to mini-
mize the power consumption in the suspend mode.