Researching & writing a 2600 emulator for 68000

[Derk]

I'm looking to code a 2600 emulator for a Motorola 68000. Essentially I'm breadboarding the computer so I can add on whatever hardware I need. I am knowledgable and experience with the 68000 instruction set.

 

Right now this is just in the planning stages.

 

I'm looking for any relevant documentation and/or tips on the software or hardware side. Ideally I'd even like to build a cartridge reader as well, but if I could just get it to play ROM images, that'd be fine.

 

Thanks in advance!

[EricBall]

The 2600 is made up of three LSIs:

 

a 6507, which is a 6502 with only 12 address lines, no IRQ, and a RDY line with a 1/3 colourburst clock

 

the TIA which handles the sprites & other graphics, sound and paddles

 

the RIOT which has the 128 bytes of RAM, timers, joysticks, buttons and switches

 

Emulating the 2600 means strict cycle counting and tracking when the game updates the TIA so the graphics can be changed at the same time.

 

It might be easier to start with the Stella or MacStella source, compile it down and go from there.