PCF8574 GPIO Extender - With Arduino and NodeMCU

In this tutorial, I am going to talk about the PCF8574 8-bit GPIO Port Extender. It is one of the many GPIO extenders available in the market.

This tiny little board becomes a life saver, When you run out of pins on your Arduino. This "GPIO (General Purpose Input Output) pin extender" provides an additional 8 pins (P0 ~ P7) which can be used to 'output a signal' or 'read a signal as an input'.
These modules run on the I2C bus, and if daisy-chined you can connect upto 8 of these devices in a project. Each device will give us an additional 8-bits of GPIO enabling 64 GPIOs in total.

Topics Covered
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- Overview of the I2C Technology ........................................ 01:57
- Closer look at the PCF8574 GPIO Extender IC and the Breakout Board .... 02:57
- GPIO Addressing ....................................................... 05:25
- Libraries To Use ...................................................... 05:48
- Connecting PCF8574 to Arduino and NodeMCU ............................. 06:32
- Finding address using I2C Scanner ..................................... 07:24
- How to program and use PCF8574 in your project ........................ 07:56
- How to use the Interrupt Pin .......................................... 09:15
- Areas of Application .................................................. 10:15

Download Links
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#PCF8574 #GPIOExtender

[Crusty_Camper]

This was very useful, thank you. As an older learner, I needed a slightly slower pace but it's easy to pause the video or play it at 75% speed, which I found excellent so as not to miss anything.

[ManuelCastillo-kqxy]

I just come to thank you for all the help you gave me to solve the issue of controlling 8 SSD relays with a single pin extender in NodeMCU.
Thank you very much for the time you gave me.

[joshuarosen]

Thank you for that informative video. You took it at a fair pace but I found it exactly right. You covered a lot of ground in 11 minutes but I understood all of it - it was very clearly presented.

[pepsodentpasta]

Thank you for sharing this video. Very clear, easy to understand, and straight to the point.

[mynkow]

Fantastic Video. I am amazed how much I have learned in 10min. Thank you

[yagothanus]

I thank you immensely, imrão you are to be congratulated for the blessed work, forward only upwards and only forwards,

[AjinkyaMahajan]

Very helpful in understanding the io expander module.
Thanks

[talktothehand]

Hello,
Very instructive post, one thing you want to be careful about about the PCF8574 modules, they already have a 1 kOhm pullup on the board (the 2 small resistors next to the male connector). If you want to daisy chain several modules, you need to remove these resistors on all but one of the board, otherwise the pullup becomes to strong ... if you daisy chain 8 modules, the pullup value is 1kOhm/8 : 125 ohm which is a bit strong : 5V/125 ohm = 40 mA...

[Siziksu]

Great quality video. Best tutorial ever about this subject. Thank you very much!

[WhatsAppVideosU]

Very nice, I loved the pace with with the information was delivered

[murrrr]

very good tutorial! before the video i didn't know what chip i have, now i not only know how to use it but also got lots of ideas where i could use it :)

[jcduplessis]

Excellent tutorial. Thank you very much!

[MhLiMz]

Excellent tutorial, thank you for creating and sharing it!

[xXRabbitmanXx]

best tutorial! straight to the point with useful information! please keep it up

[nbabasketball]

I will book mark 07:10 that's an important information for starters

[kamlishpandit]

dear really mind-blowing explanation. superb.

[sandrosales]

Excelente vídeo, parabéns e obrigado !!

[CodeBallast]

i have no electronics skills.

This Tutorial was easy to understand.

What are the two pull up resistors good for?

A0, A1 and A2 how do you set their address? Are you just giving them 3, 3 volts?

[rondlh]

Great job, very clear and informative

[sanjaybatra]

Its really great presentation. I used it, interface 4x4 keypad. I had a little issue...which automatically gone without any efforts.
Issue 1. LCD start flickering, then somehow it got stable, when I removed SDA and SCL wires.
Issue 2. For testing purpose, I am doing ON/OFF of one LED, which Stoped when I connected/Disconnected SDA/SCL.
After Switching OFF/ON the power, LCD and LED both working fine.
What you suggest ? do SDA/SCL connection impact on other things ?
Any Capacitor or something required ? Value of PULLUP resistor ?
(this exercise was done with RAW atmega16A chip).