2008 Microchip Technology Inc.
DS22103A-page 5
MCP23018/MCP23S18
1.1
Pin Descriptions
TABLE 1-1:
I2C PINOUT DESCRIPTION (MCP23018)
Pin
Name
28L
PDIP/
SOIC
24L
QFN
24L
SSOP
Pin
Type
Standard Function
GPB0
3
24
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.
GPB1
4
1
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.
GPB2
5
2
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.
GPB3
6
3
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.
GPB4
7
4
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.
GPB5
8
5
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.
GPB6
9
6
8
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
9
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.
VDD
11
8
10
P
Power
VSS
1
23
1
P
Ground
SCL
12
9
11
I
Serial clock input
SDA
13
10
12
I/O
Serial data I/O
ADDR
15
11
13
I
Hardware address pin allows up to 8 slave devices on the bus
RESET
16
12
14
I
Hardware reset
INTB
18
13
15
O
Interrupt output for port B. Can be configured as active high, active low, or
open drain.
INTA
19
14
16
O
Interrupt output for port A. Can be configured as active high, active low, or
open drain.
GPA0
20
15
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.
GPA1
21
16
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.
GPA2
22
17
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.
GPA3
23
18
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.
GPA4
24
19
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.
GPA5
25
20
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.
GPA6
26
21
23
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
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.
NC
2, 14,
17, 28
—
Not connected
EP
—
25
—
Exposed Thermal Pad (EP). Do not electrically connect, or connect to VSS.