> manchester encoding might be an option

I think Manchester would generally be the weapon of choice. If
you don't have enough INT or IOC pins multiple inputs can be
dealt with under timer interrupts. It's all basically waiting and
sampling

Joe
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.