This board was designed to aid in development with the Commander X16 project by The 8-Bit Guy. It is used to test the proposed video solution, the Gameduino v1, by allowing code to be written on a Commodore 64 or 128 and passed through the user port. The board provides 3.3v to the Gameduino and can be safely powered by the Commodore User Port 5v supply. The board can also be configured to work with the Gameduino 2 or 3, but external USB power or a larger than stock Commodore power supply is required. Also included are two PS/2-style 6 pin mini-din ports. Each has two data pins exposed as well as 5V and ground. The idea is to use them with a keyboard or mouse, but they could be used with any device you desire. One of these ports must be disabled to use the Gameduino 2 or 3 as they use more pins than the Gameduino 1.
This is a 1.0 version of the board, and contains two errors. Initially, we believed the Xilinx Spartan3 series of FPGAs (used on the Gameduino) to be tolerant of 5V signals. However, upon further inspection we found the max to be 4.6v, and ideally, 3.3v. The resistors added to the bottom of the board are not ideal, but do drop the signal level into the safe range for the Spartan3. Pin PB2 on the bottom silkscreen is also misprinted. PB2 should read: SPI_MISO not SPI_MOSI.
Initially, we were planning to make a new version of these boards to address the problems, but the next phase in video is moving forward rapidly. The parallel code for the Gameduino is coming along and it makes little sense to run another set of these boards. We will instead start working on the parallel version soon and decided to release these in very limited quantity for anyone who would like to have one.
We are making the schematic available. You may download these files here: Gameduino SPI schematic.pdf
Technically, there is one further error. The boards say “Commander 16” on the front. This was actually not a misprint, but what the name was briefly before it changed to Commander X16. If you want to know more about the Commander X16 project, have a look at David’s video about his Dream Computer. Discussions about David’s Dream Computer can be found in the Commander X16 Protoype Facebook group.