Re: C=Key testing

From: Groepaz (
Date: 2004-09-22 13:01:17

On Wednesday 22 September 2004 08:47, Jim Brain wrote:

> The idea is to watch the ROW and COL pins and when any go low, place the 
> corresponding lows on the other half corresponding to which keys are 
> pressed at that time.
> I've pertially implemented it, and (notwithstanding that the Mapping the 
> 64 book seems wrong when it states WRITE to PORTA and READ from PORTB), 
> it is working...

what did you use for testing? there are keyscanners that work either way,
maybe it even changed across different versions of the kernel (thats just
a wild guess, i actually dont think that is the case).
> However, if you hold a key down, the repeat is erratic.  As well, if you 
> just press and release a key, often I get doubled or tripled chars.
> So, my questions:
> Anyone have any experience in keyboard scanning routines on the 64?

i've written some stuff in that area for my (unreleased, shame on me :=P)
sid tracker.... what you describe seems odd, are you sure your hw does
what its supposed to. (mmmh, ok, dumb question, you wouldnt be asking... :=))

i would suspect that multiple keypresses are generated or picked up by other
means from the ps/2 keyboard....what are you using, the key-press and key-release
or the actual keycodes?

> Anyone with a DSO or logic analyzer who wants to help test?


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