Dutch wrote:
To: Lukazi On 2009-04-29 20:35:12 -0600, Lukazi <lukazi@hotmail.com> said: <snip>Now that I have completed it you can see the Atari Joystick to Apple II's "Atari Joyport" converter here in my blog: http://lukazi.blogspot.com/2009/04/game-controller-atari-joysticks.html< snip>Cheers, Alex.This is pretty cool. I built this over the weekend from the schematic on the blog, and wrote a quickie program to test the logic. I noticed some additional diodes have been added to the circuit. Mine seems to work fine without them. What benefit does this add, and is D3 backwards?
No mistake. The diodes protect the mux outputs from being shorted by the simultaneous actuation of the Apple keys or the Shift key (if the shift key mod is installed). The PB2 diode is reversed because the Shift key grounds the PB2 input, while the Apple keys connect PB0 and PB1 to +5v. PB0 and PB1 are pulled down by 470 ohm resistors in the keyboard, while the shift key mod pulls PB2 up. -michael ******** Note new website URL ******** NadaNet and AppleCrate II for Apple II parallel computing! Home page: http://home.comcast.net/~mjmahon/ "The wastebasket is our most important design tool--and it's seriously underused."