Retrode SMS/GG plug-in adapter follow up
Posted 3 months ago
I have been going through my Game Gear and Master System games, trying them out with the SMS/GG Plug-in adapter and have noticed two things:
- The Game Gear connector needs to be secured.
- Game size detection is a little flaky.
Game Gear connector - Every time you insert/remove a Game Gear game, the connector moves a bit as it is only secured by the solder joints. Now this might not seem like much of an issue, but over time, it could cause the solder joints to fail. In the Game Gear, the connector is held in place with two rivets (see photo below), the plug-in adapter could do with two holes to secure it in a similar way. I mentioned it to Matthias and he said that the production Adapter will have such holes, perfect.
Game Gear PCB
Game size detection - The first few cartridges I tried with the adapter worked fine, the resulting ROM files were the correct size and they loaded straight up in an emulator. As I tried more, I started to notice that some of them were not working, mainly because the ROM files were smaller than they should be. Lets take Super Monaco GP as an example, it is a 256KB cartridge which the Retrode makes a 128KB ROM file from.
It isn’t the Retrode that’s at fault here, its the cartridge (or the games programmer).
The SMS/GG ROM header has a location that specifies the ROM size (0x7FFF), and it turns out that quite a few games (seems to be mostly games larger than 128KB from my experience) don’t have the correct size there, they have a smaller size listed. The Retrode looks here to work out what size to make the ROM file, and if it is wrong in here, the file you get is the wrong size and doesn’t work. In this instance, Super Monaco GP has $F (128KB) at 0x7FFF, which is wrong (it should be $0 (256KB).
Super Monaco GP SMS header screenshot (location 0x7FFF highlighted)
Luckily, the Retrode is a clever beast. As of firmware v0.16a, there has been an overdump function. The HWB button cycles between auto size detection and 3 predefined ROM sizes. Using this feature I set the size to 256KB, and what do you know, I had a working ROM file! I was able to get all the other non-working games to work using the same method.
It won’t be a problem with every game you use, but it is something to bare in mind when using this adapter.
