Datasheet
MCP23018/MCP23S18
DS22103A-page 6 © 2008 Microchip Technology Inc.
TABLE 1-2: SPI PINOUT DESCRIPTION (MCP23S18)
Pin
Name
28L
PDIP/
SOIC
24L
QFN
Pin
Type
Standard Function
GPB0 3 24 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB1 4 1 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB2 5 2 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB3 6 3 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB4 7 4 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB5 8 5 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB6 9 6 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPB7 10 7 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
V
DD
11 8 P Power (high current capable)
V
SS
1 23 P Ground (high current capable)
CS 12 9 I Chip select
SCK 13 10 I Serial clock input
SI 14 11 I Serial data input
SO 15 12 O Serial data out
RESET 16 13 I Hardware reset (must be externally biased)
INTB 18 — O Interrupt output for port B. Can be configured as active high, active low, or open
drain.
INTA 19 14 O Interrupt output for port A. Can be configured as active high, active low, or open
drain.
GPA0 20 15 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA1 21 16 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA2 22 17 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA3 23 18 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA4 24 19 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA5 25 20 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA6 26 21 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
GPA7 27 22 I/O Bidirectional I/O Pin (5.5 volt tolerant inputs; open-drain outputs). Can be enabled
for interrupt on change, and/or internal pull-up resistor.
NC 2, 17,
28
— Not connected
EP — 25 — Exposed Thermal Pad (EP). Do not electrically connect, or connect to V
SS.