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Adafruit MCP23017 Arduino Library Build StatusDocumentation

This is a library for the MCP23008/17 I2C and MCP23S08/17 SPI Port Expanders.

Adafruit invests time and resources providing this open source code, please support Adafruit and open-source hardware by purchasing products from Adafruit!

Written by Carter Nelson for Adafruit Industries. BSD license, check license.txt for more information All text above must be included in any redistribution

To install, use the Arduino IDE Library Manager.

Pin Addressing

When using single pin operations such as pinMode(pinId, dir) or digitalRead(pinId) or digitalWrite(pinId, val) then the pins are addressed using the ID's below. For example, for set the mode of GPB0 then use pinMode(8, ...). NOTE The MCP23008 and MCP23S08 only have GPAx pins.

MCP23x08 Pin #

MCP23x17 Pin # Pin Name Pin ID
10 21 GPA0 0
11 22 GPA1 1
12 23 GPA2 2
13 24 GPA3 3
14 25 GPA4 4
15 26 GPA5 5
16 27 GPA6 6
17 28 GPA7 7
-- 1 GPB0 8
-- 2 GPB1 9
-- 3 GPB2 10
-- 4 GPB3 11
-- 5 GPB4 12
-- 6 GPB5 13
-- 7 GPB6 14
-- 8 GPB7 15

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