Programming burttons - Ic21 and MCP23017

Projects General Guidance
1

I saw a great post on Nick Gammon's website on using the
MCP23017 port expander to read button presses - possibly to eliminate the
issue I currently have using the Adafruit RGB LCD shield - where polling is required to
read the buttons - I get problems depending on how long (or how short) I press a button.

It seems this link may be the answer:http://www.gammon.com.au/forum/?id=10945
It is not clear to me how (or if) I can tell which button has been pressed.
My application requires five buttons, and I need to know which one is pressed (UP,DOWN,LEFT,RIGHT,SELECT).

I tried to post a reply on the Gammon forum, but for some reason cannot post a reply to his
great information.

Any suggestions will be greats.

Thanks

eholz1

2

Then example code in Nick's article shows how to read the interrupt flag registers to determine which input (switch) caused the interrupt.

3

Hello,

I will check and try the code posted in Nick's forum,

thanks