Hi all,

I have only 1 pin available in a PIC16F micro but need to read 5-10
momentary buttons, and do not want to use any other additional external IC.
I figured out a way to work this out using 1 single A/D pin to differentiate
each button from the rest, provided I have different R-R bridge for each
button, therefore if no button is pressed the A/D should read 5V, but as
soon as a button is pressed, a R would move that to, say, 2.8V. If all the
resistor combination are different and I can work with at least
0.25Vdistance between them (
e.g. 0.25V, 0.50V, 0.75V, 1V, etc), looks like a robust and solid solution
to me.

Only drawback I can see is no multiple buttons can be pressed at a time and
give a valid value, but this is not a requirement.

Do you see any problem with this approach? Anybody used something like this
before? Any other option you can suggest for multiple buttons, 1 pin and no
additional circuitry?

Thanks in advance.

-- 
Ariel Rocholl
Madrid, Spain
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist