Emulate GameBoy Color's GameLink

Question

I'm currently developing a GameBoy Color Emulator for learning purposes. I also wanted to emulate the GameLink functionality (poké-fight ftw!), but I did not found any documentation, examples, references or source snippets on how to emulate the GameLink.

All GameBoy emulators I found on github didn't provide this functionality.

Programming Language doesn't matter, I'm just curious if there are resources on that topic out there.

Has anybody an idea on where to start with this feature?

Answer 1

A few links that might prove useful :

 http://image.diku.dk/projects/media/kirk.06.pdf
 http://www.hardwarebook.info/Game_Boy_Link
 http://fms.komkon.org/GameBoy/Tech/Hardware.html

The key appears to be to search G for gameboy gamelink protocol.

Apologies if you already know of them

Answer 2

I'm willing to bet that, almost four years later, you no longer care but the No$ documentation covers the serial port.

$FF02 is a control port, $FF01 is a data port.

The transmitter is expected to queue up a byte in $FF01 then post a byte to $FF02 indicating that: (i) a transfer should start; (ii) using an internally-generated clock.

The receiver should use $FF02 to configure its port as expecting an internal clock. When it receives a byte it can inspect it via $FF01.

Sending or receiving a complete byte sets bit 3 of the interrupt register. So the receiver knows when it has received a byte by servicing that interrupt, and the transmitter similarly knows when it can send the next.