Interface & Bus 28 pins

MCP23017 I2C I/O Expander

16-bit I2C I/O expander. 8 devices per bus, interrupt support, configurable pull-ups.

// connector diagram 28 pins

// loading diagram...

// Specifications

Supply Voltage

1.8V – 5.5V

I/O Pins

16 (two 8-bit ports)

Interface

I2C (up to 400 kHz)

I2C Addresses

0x20–0x27

Pull-ups

Internal configurable

Package

DIP-28 / SOIC-28

// Pin Reference Table

Pin	Name	Function	Type
1	GPB0	Port B bit 0	I/O
2	GPB1	Port B bit 1	I/O
3	GPB2	Port B bit 2	I/O
4	GPB3	Port B bit 3	I/O
5	GPB4	Port B bit 4	I/O
6	GPB5	Port B bit 5	I/O
7	GPB6	Port B bit 6	I/O
8	GPB7	Port B bit 7	I/O
9	VDD	Supply voltage	PWR
10	VSS	Ground	GND
11	CS	Chip select (SPI mode) / NC	I/O
12	SCL	I2C clock	BUS
13	SDA	I2C data	BUS
14	A0	I2C address bit 0	I/O
15	A1	I2C address bit 1	I/O
16	A2	I2C address bit 2	I/O
17	RESET	Reset, active low	I/O
18	INTB	Interrupt for port B	I/O
19	INTA	Interrupt for port A	I/O
20	GPA0	Port A bit 0	I/O
21	GPA1	Port A bit 1	I/O
22	GPA2	Port A bit 2	I/O
23	GPA3	Port A bit 3	I/O
24	GPA4	Port A bit 4	I/O
25	GPA5	Port A bit 5	I/O
26	GPA6	Port A bit 6	I/O
27	GPA7	Port A bit 7	I/O
28	VDD	Supply voltage	PWR

The MCP23017 is a 16-bit I2C I/O port expander by Microchip. It provides two 8-bit GPIO banks (PORTA and PORTB) with configurable pull-ups, interrupt-on-change, and up to 400kHz I2C. Up to 8 devices per bus (128 extra GPIO pins).