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I2C Port Extender

Posted: Tue Jun 26, 2012 10:33 am
by zeeMonkeez
I've made a (stackable) I2C port extender module using the MCP23008. Schematics and board are here: .
Comments welcome.
I have a few prototypes of v1.0 where I've buggered up the /RST input, but it works fine if just pulled up high. I'm happy to sell them at cost, shipping to UK/EU.

Re: I2C Port Extender

Posted: Tue Jun 26, 2012 1:43 pm
by zeeMonkeez
Here is a pic of the schematic:
And here is one of my prototypes lighting up a couple of LEDs:

Re: I2C Port Extender

Posted: Tue Jun 26, 2012 7:04 pm
by TonyD
I see your MCP23008 and raise you a MCP23017 :-)

I've done a similar board but I used the MCP23017. Details here

Your board looks nice and neat.


Re: I2C Port Extender

Posted: Thu Jun 28, 2012 5:49 pm
by Pepepaco_82
Looks really great, many thank for this open project

I don't have my pi yet, and I'm not sure at all about witch i2c driver select to manage your board, or how to do it exactly.
I gather reading forum the first step is recompile the kernel with the i2c driver, this method?

And after that I think the better option is create your own header files with functions to manage the i2c, I'm right?
Are any manual, or code examples to learn how to set up the port extender and after that how to call him from a bash or phyton program?

It will be great for beguinners like me...