>
>
> They're called "vertical" because you don't have a byte associated to an
> input pin and count through the bits of that byte -- that would be
> "horizontal" --, instead you have a bit associated to an input pin and
> count through several instances of this bit in different bytes. Less waste
> of storage (most of the bits in the "horizontal" counters are not used)
> and
> less instructions (you may be able to read a whole port into a byte of a
> vertical counter -- the data comes already in a "vertical" format).


Hmm.. I think I see, I need to work through an AVR implementation.

In a recent case, I took an 8 bit keypad and debounced it with a single
byte, but what I was doing was treating the byte as a single entity. My
rules required that I see no change on any of the bits until the timer
expired.

Not sure this description was clearer :)  but it's hard to describe
> vertical counters in words.


:)  I think that's my problem, I'm having a hard time picturing it.

It's a fun business we're in, some things are so simple, yet so hard to
describe.
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