How to connect the MCP23017 GPIO Expander to an Arduino and Raspberry Pi

In this episode, we take a look at the MCP23017 GPIO Expander IC. With this IC, we can add 16 GPIO pins to the existing GPIO pins on an Arduino, Raspberry Pi, or any micro controller that has an i2c bus. They can be "stacked" for up to 128 additional GPIO pins! Bring on the LED's!

In this video we cover:
► Physical connection of the MCP23017 to a Raspberry Pi
► Code examples for the Raspberry PI in Python
► Physical connection of the MCP23017 to an Arduino UNO
► Code examples for the Arduino

As promised, all the code used in this video is on Github!

Parts that were used in this video:

Now go get creative! Share what you have made with me. I can be found at

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See ya next time!

#arduino #raspberrypi #makers

[DevonsWorkshop]

Working on a 16 step switch project. Each key has an embedded led. For 16 switches I actually need 32 gpio. Your video helped me to figure out how to work with this chip properly with a Pi Pico. Very helpful video! Thank you.

[YoBrewster]

Sounds like this is what I might need to control my custom pin on a budget :)

[aryansatpathy]

This is soo helpful, I couldn't find any proper explanation anywhere else
Helped me for my project

[samk]

Happy to stumble across your channel. Clear and concise, thank you!

[croll_uk]

Tip: Check the Red & Blue lines on the power rails for any breaks that indicate power termination. Nice video, subbed :D

[deanhuff]

Very helpful. I’m attempting to revive the old diamond rio MP3 player parallel interface so I can get some new music on my 23 year old MP3 player :)

[MattRose]

Are the indicator LEDs at the left just wired between VCC and ground? Do I not need a resistor?

[rccowboys]

I really need to know how I can chain these together in a RPI3B+. Also How many can be chained together? Are the bandwidth considerations? I am trying to figure out a way to hook up about 20 stepper motors and a camera with a few sensors also. BTW awesome channel. Thank in advance for your reply.

[chuckhole]

Check the datasheet to confirm that you don't need a resistor on the Reset pin. Connect it directly to the positive supply.

[YoucefYazid]

Hello, At first thanks for informations, just i want to ask why we use R 1K to reset pin?

[pruch]

thanks dude!!!, you saved my life, get my like

[_teknq]

I am somewhat new to using the Raspberry Pi (3 B+) and I would like to expand my GPIO as shown in this video. I already have a 20x4 LCD display using pin 3 (SDA.1) and pin 5 (SCL.1). Can pin 27 (SDA.0) and pin 28 (SCL.0) be used instead to setup the expansion board while the LCD display is still connected to pin3 and pin 5?

[abdulkarim.jamal.kanaan]

thank you very helpful video. one question, if modify the speed of i2c on raspberry, what the maximum number of chips we can use?

[dfmayes]

I wouldn't recommend hooking up with power applied. Connect, check, then apply power.

[JeroenUE]

Nice explaining!! How can I use this in Domoticz?

[jenniferw]

Have you measured how many microseconds it takes for digitalRead() and digitalWrite() using these 16 GPIO pins via I2C compard to the pins which come on the microcontroller? Just wondering how much slower it is. Hopefully it doesn't take more than say 100 microseconds.

[djsbriscoe]

Can you do a video on how to use this to control 1 or 2 i2c modules (say an I2C LCD to start with) using the arduino. For instance, how would you read from an I2C module and write to an I2C LCD through the MCP23017 (or MCP23S17 for SPI). Thanks.

[muaddibinho]

Damn this was good. Subscription added!

[qozia]

What about esp32 running micropython? Thanks.

[roystervi]

hi is it possible to have the Arduino and Raspberry Pi connected to the same ic2 line at the same time?