Reading a keypad with an MCP23016

Newzed

Here is a tidy little program that will let you read the state of a keypad having up to 16 buttons.· We used a 12-button keypad - BG Micro SWT1068.· Keypads must have a common ground with lines for each button.· All buttons are held high with a 10K resistor to Vdd.· The program contains all the connections for the MCP23016 and the keypad.· This is for a bus type keypad only - it won't work with a matrix keypad.

The program uses only two I/O ports - 8 and 9 - and has only·two 1-byte variables.· It is written for the BS2P, but I have a modified code for the BS2/BSE if you need it.· I used my MCP23016 piggyback but any breadboard configuration will work just as well.


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Post Edited By Moderator (Jon Williams) : 4/12/2005 11:07:46 PM GMT

dandreae

Sid,

Add a schematic to this and post it under "Projects".· This project is very popular, thank you for posting this.

Dave

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Dave Andreae

Tech Support
dandreae@parallax.com
www.parallax.com

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Newzed

Dan, the only medium I have for making a decent schematic is ExpressPCB, and you can't copy and paste things from there.· Maybe I could take a screen shot and then post that.

Sid

Mrdavidjenkins

This looks very handy and any code or documentation you could provide will be much appreciated by a lot of people.· Thanks for the post

Chris Savage

·· Yeah, Sid's one of our home-brew hackers who manages to get more projects done in a week than I do in a· month!· LOL· I see the schematic made it online.

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Chris Savage
Parallax Tech Support
csavage@parallax.com