From: Jim Brain (brain_at_jbrain.com)
Date: 2007-05-09 08:56:20
Daniel O'Shea wrote:
> I was wondering, in both Jim and Levente's microcontroller to joystick
> port projects - is interfacing a microcontroller's digital output
> (high/low) to the joystick input likely to cause the same issues with
> the CIA chip as noted here:
>
> http://www.floodgap.com/retrobits/ckb/display.cgi?26
>
> Message was sent through the cbm-hackers mailing list
I doubt either of our projects has this issue. In mine, for example, IO
is done thusly:
output to joy DDR logic level notes
HI input high internal
pullup engaged
LO output lo tied
directly to ground (well, close to it)
LO->HI: switch DDR to input, then switch logic level to high to engage
pullup. Doing it this way ensures you never drive pin with 5v directly
HI->LO: disengage pullup, then switch DDR to output.
Jim
--
Jim Brain, Brain Innovations (X)
brain@jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!
Home: http://www.jbrain.com
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