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Subject: Re: unreliable buttons? try this
From: Glenn Ervin at Home (
Date: 2004-07-04

Could this problem possibly be solved by adjusting the scrolling speed?
----- Original Message -----
From: "John Donahue" <>
To: <>
Sent: Saturday, July 03, 2004 9:43 PM
Subject: Re: unreliable buttons? try this

Thanks for trying to solve this problem.
I'm convinced that its only during the release of the button that the
problem occurs. Looking at the flashing numbers in the debug section, when a
button is released it doesnt always go from say 200 down to 000 cleanly.
Sometimes a 100 will briefly show. I've always noticed the mechanism for
button release feels a lot more 'gradual' than the 'click' when its pressed.
I tried your fix and I indeed wasnt able to trigger a false positive
buttonwise. F2 was a little sluggish for me but works. Two rapid pushes of
any button didnt register the 2nd push however, so I wouldnt suggest this
build for tetris ;)

Maybe instead just check that the reading goes back down to zero before
allowing a lesser but non-zeroish value. like allow all the 26F's during a
button hold but ignore that 1D2 upon release since it didnt go down to zero
first. But, allow number changes that go higher as would result from button
combinations. um, also the release of one of the buttons after a combo press
should be recognized as ok i guess...

Several people reported unreliable button detection by Rockbox, sometimes
there are misinterpretations. You can stop reading if you don't suffer from

I have added a kind of "debouncing" to the button code. Now, a button is
only valid if the analog port reported several stable readings within a
certain "corridor". Please test it and report if this is an improvement. The
corridor may be too strict, causing dead buttons. So try the .ajz via rolo
first, flash later, or you need the F1-start. ;-)

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Page was last modified "Jan 10 2012" The Rockbox Crew