Aha, I wonder if maybe that board is from some kind of redemption game. Seems like a board like that would cost too much for a home game, let alone a handheld.
That's very possible- there's edge fingers on the board where spade terminals plugged in it looks. I will do a full board trace in a few days maybe.
Have you dumped any Rockwell chips, especially the PPS4/1 MCUs like the MM76EL? The data sheets mention a test mode to verify ROM contents, but I haven't found any details. When I have some time I'll try activating the test pin and see if I get lucky and it just starts spitting out data, like the COP444L.
Not yet, but I will poke it soon. I bought a game (Mattel World Championship Football) that has no less than TWO MM78 chips in it. I have them removed and was going to try and poke around with the test pin to see if I get lucky.
I have a COP411 to dump also but there's a complete procedure fully documented to dump them so I'm not worried there. It's the sound chip in the handheld Turtles game. Nope it's not the same as the one on the Adventure vision even though both are made by entex.
There's another mitsubishi CPU that's in the Coleco Frogger tabletop that also seems to have a test pin. I hope I can dump that as well. The datasheet calls it by a strange name which implies it's probably a test pin.
Also, do you have any info on Rockwell calculator chips? We've been trying to figure out the Mattel handhelds, which seem to be B6001 and B6100 series chips, but haven't found anything but a few mentions in magazine articles and a couple of patents. I bought a couple of calculators with Rockwell chips, but they both are PPS4/1s, and the B6001 is much simpler.
Not a thing unfortunately. I have one of those mattel football games with the chip in it. It's board-only and the chip is dead from what I recall so you can have it if you want it for decapping.
My handheld directory is located here with dumps, pictures, and pinouts for all the things I have worked on:
Once Hap verifies my HD388xx dumps (hint hint :-) I will dump the other HD38820's. I won't remove them from the adapters until they are verified. I'm 99.9999% sure the code on them is good but the proof is in the emulation. We really need that HMCS programming manual. I know it's being scanned so hopefully that will be done soon.