What are the differences between Colecovision and SG-1000?

[AceFace]

Hey guys,

I've been reading tons on the hardware inside the machines and everything I could about the various console mods that have been done for the Sega Genesis and the Master System for the past several weeks. Finding out about the Dina 2 in 1 got me really wondering just how far modifications can go.

I'm aware that the Dina ran both Colecovision and Sega SG-1000 games, as both machines used the same principal chips. What I'm wondering is, did the Dina have additional stuff crammed into it to accomodate both systems, or were the two systems built that similarly? More specifically, being that a Master System is built to be backwards compatible with the SG-1000, but is more advanced, could it likewise be modified to play Colecovision cartridges?

If so, I'm wondering why I haven't seen anyone do it. I'm guessing all you'd have to do is attach the right cart slot, maybe change the BIOS, and possibly tinker with the way the controllers are read. Anyone got any knowledge on that?

[Maxim]

They have different memory and I/O layouts internally so you'd have to replace the I/O chip in the Master System to get the Colecovision compatibility. The controllers would probably need all new connections too. This is in the realm of super hard to do.

[AceFace]

So basically it's one or the other? A system that could handle both is unlikely?

[Maxim]

In theory it's doable but it's way too much work for the result. ROM hacks might be more feasible.

[AceFace]

That's disappointing. Is that due to the changes in the Master System, or would it be just as difficult with an SG 1000?

[Maxim]

Mostly the same deal.

What Colecovision game is worth the effort?

[AceFace]

Honestly, I just thought it would be fun to tinker with a machine that could do both. And I was kind of digging some of the Colecovision expansion modules.