XR20M1172_09 Datasheet, PDF (3/58 Pages) Exar Corporation – TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO

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PIN DESCRIPTIONS
XR20M1172
TWO CHANNEL I2C/SPI UART WITH 64-BYTE FIFO
Pin Description
NAME
32-QFN
PIN #
28-TSSOP
PIN#
TYPE
DESCRIPTION
I2C (SPI) INTERFACE
SO
2
SDA
3
RXB
4
RXA
5
TXA
6
TXB
7
XTAL1
9
XTAL2
10
GPIO2/CDB#
11
GND
12
GPIO0/DSRB# 13
GPIO3/RIB#
14
RTSB#
15
5
O _{SPI data output pin. If SPI configuration is selected then this pin is a}
three-stateable output pin. If I2C-bus configuration is selected, this pin
is undefined and must be left unconnected.
6
O _I2_{C-bus data input/output (open-drain). If SPI configuration is}
selected, then this pin is undefined and must be connected to VCC.
7
I _{UART Receive Data or Infrared Receive Data. UART receive data}
input must idle HIGH. Infrared receive data input must idle LOW. If this
pin is not used, tie it to VCC or pull it high via a 100k ohm resistor.
8
I _{UART Receive Data or Infrared Receive Data. UART receive data}
input must idle HIGH. Infrared receive data input must idle LOW. If this
pin is not used, tie it to VCC or pull it high via a 100k ohm resistor.
9
O _{UART Transmit Data or Infrared Encoder Data. In the standard UART}
Transmit Data mode, the TX signal will be HIGH during reset or idle
(no data). In the Infrared mode, the inactive state (no data) for the
Infrared encoder/decoder interface is LOW. If ithis pin is not used, it
should be left unconnected.
10
O _{UART Transmit Data or Infrared Encoder Data. In the standard UART}
Transmit Data mode, the TX signal will be HIGH during reset or idle
(no data). In the Infrared mode, the inactive state (no data) for the
Infrared encoder/decoder interface is LOW. If ithis pin is not used, it
should be left unconnected.
11
I _{Crystal or external clock input.}
12
O _{Crystal or buffered clock output.}
13
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.
14
Pwr _{Power supply common, ground.}
15
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.
16
I/O _{General purpose I/O pin or UART Ring-Indicator. 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.
17
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.
3