Wiring Commodore-16
Due to having more input and outputs pins, this board is the best choice for the Keymmodore Project if you want to have less work on the wiring. With this board keyboard and joysticks have their own separate pins.
Also, another nice feature, is the fact that the C-16 Keyboard connector can be plug directly to the board, there is no need to extensions or adaptors. Just solder a 19-pin male strip to the Teensy (from C7 to B7). Aldo don’t forget to remove the 2nd or «key» pin.
The resistors value for the LEDs can change. I choose those looking for colors not being too bright but also uniform. Don’t forgert to insert the resistor for the power LED in case you go for that choice.
The drawing of the DB-9 connectors for joysticks are inverted to make the diagram easier to read. Look at the corresponding pin numbers. Remember this is optional.
Wiring Plus/4
Plus/4 can be a little tricky due to having a ribbon type cable. I suggest getting a 18 pin female ribbon cable connector (or desolder it from the original board). Check orientation of Pin 1. It’s the closest one to the Plus/4 LED.
Keep in mind, Plus/4 has the red LED connected to pins 3 and 4 so those pins will actually supply 5V (when LED is On) from the Teensy board.
The drawing of the DB-9 connectors for joysticks are inverted to make the diagram easier to read. Look at the corresponding pin numbers. Remember this is optional.
An advice about Pin D6
Pin D6 has a LED connected to it. You can identify the Pin and the LED indicated with a red rectangle in the picture. If you have a weird behavior, like «ghost» keys pressed, remove the LED. I’ve found some strange issues because of the LED with some boards. E.g: The left/right cursor key, also «press» the colon key.
It can be easily removed with your soldering iron.