XR20M1172G28-0B Datasheet, PDF (4/55 Pages) Exar Corporation – TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO

XR20M1172
TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO
Pin Description
REV. 1.2.0
NAME
CTSB#
32-QFN
PIN #
16
SCL
17
ENIR#
18
EN485#
19
IRQ#
20
RTSA#
21
GPIO5/DTRA# 22
GPIO1/DTRB# 23
RESET#
24
CTSA#
25
GPIO4/DSRA# 26
GPIO6/CDA#
27
28-TSSOP
PIN#
TYPE
DESCRIPTION
18
I _{UART Clear-To-Send. This input can be used for Auto CTS Hardware}
Flow Control or as a general purpose input. If unused, this pin should
be connected to VCC or GND.
19
I _I2_{C-bus or SPI serial input clock. When the I}2_{C-bus interface is}
selected, the serial clock idles HIGH. When the SPI interface is
selected, the serial clock idles LOW.
-
I _{Enable IR Mode (internal pull-up resistor). This pin is sampled upon}
power-up. If this pin is HIGH, then the TX output and RX input will
behave as the UART transmit data output and UART receive data
input. If this pin is LOW, then the TX output and RX input will behave
as the infrared encoder data output and the infrared receive data input.
-
I _{Enable Auto RS-485 Half-Duplex Mode (internal pull-up resistor). This}
pin is sampled upon power-up. If this pin is HIGH, then the RTS# out-
put can be used for Auto RTS Hardware Flow Control or as a general
purpose output. If this pin is LOW, then the RTS# output is the Auto
RS-485 Half-Duplex direction control pin.
20
O _{Interrupt output (open-drain, active LOW). For proper operation, a}
pull-up resistor is required on this pin.
21
O _{UART Request-To-Send. This output can be used for Auto RTS Hard-}
ware Flow Control, Auto RS-485 Half-Duplex direction control or as a
general purpose output. If unused, this pin should be left uncon-
nected.
22
I/O _{General purpose I/O pin or UART Data-Terminal-Ready. If this pin is}
an input and is unused, it should be connected to VCC or GND. If this
pin is an output and is unused, it should be left unconnected. See
IOControl[1] and IODir register.
23
I/O _{General purpose I/O pin or UART Data-Terminal-Ready. If this pin is}
an input and is unused, it should be connected to VCC or GND. If this
pin is an output and is unused, it should be left unconnected. See
IOControl[1] and IODir register.
24
I _{Reset (active LOW) - A longer than 40 ns LOW pulse on this pin will}
reset the internal registers and all outputs. The UART transmitter out-
put will be idle and the receiver input will be ignored.
25
I _{UART Clear-To-Send. This input can be used for Auto CTS Hardware}
Flow Control or as a general purpose input. If unused, this pin should
be connected to VCC or GND.
26
I/O _{General purpose I/O pin or UART Data-Set-Ready. If this pin is an}
input and is unused, it should be connected to VCC or GND. If this pin
is an output and is unused, it should be left unconnected. See IOCon-
trol[1] and IODir register.
27
I/O _{General purpose I/O pin or UART Carrier-Detect. If this pin is an input}
and is unused, it should be connected to VCC or GND. If this pin is an
output and is unused, it should be left unconnected. See IOControl[1]
and IODir register.
4