Wednesday, December 9, 2009
Keyboard connected, up and running!
On Dec 8 at 1:15AM I finally had reset working and dropping into the monitor program. After building the keyboard circuit, I keyed in the test program from the Apple 1 manual. Eureka! Well, one board works (the one that came with the kit). The board I built from scratch components doesn't pick up keyboard events yet, so this board will need additional debugging. But as you can see on the board that works, the ASCII charset is being dumped repeatedly just like it is supposed to.
I started the night with building the Apple II keyboard -> Apple 1 mapping circuit based on WSander's mapping schematic. I did not wire up the Repeat -> Clear mapping yet (which requires one trace modification on the keyboard).
Pin 1 (+5v) on the Apple II keyboard ribbon cable was broken clean off, so I had to separate the wire from the ribbon. I did this with an Exacto blade. Then I extended it about 5 cm by soldering another piece of wire. I didn't have any heat-shrink on hand, so I had to use electrical tape to cover up the bare connections. This made the wire long enough to sneak it underneath and into the DIP socket. As you can see in the photos, I used 16 pin ZIFF sockets on each of the ribbon cables. I also added a DIP socket to each end of the ribbon cable to protect the pins.
One thing worth mentioning, as I am not that familiar with Apple II keyboards -- there is a switch on this particular 1979 model, underneath the keyboard on the encoder PCB. This switch has 2 settings: Ctrl and Reset. My keyboard Reset button did not work until I flipped the switch from Ctrl to Reset.
Posted by John at 2:56 PM