I've looking for one of this rare peripheral, the Mega Mouse: Sometimes, you can find one or some for sale in eBay, but they're expensive. Physically, the Mega Drive/Genesis pad port is like a PC CS232 serial port. I also thought if you can connect an old PC mouse to the console but obviously is impossible. I ask you if you think it's possible to make some changes in order to do compatible an old serial mouse or even modifying a modern USB mouse. I only found this approach between computer and Mega Drive mouses: http://eab.abime.net/showthread.php?t=65346
It could be done. You could scrap a 74HC157 from a beat-up controller, some of the elements of an old trackball mouse, and make your own design. Here is some info on how the 6-button behaves: https://www.cs.cmu.edu/~chuck/infopg/segasix.txt Alternatively.. you could trim down/fold-and-stack the beat-up controller's PCB, convert the d-pad contacts into a custom X/Y trackball mechanism, and A/B/C into your buttons. Best of luck.
Finally I bought a Mega Mouse, very cheap, indeed. I had made some photos of the inside: When I had time I'm planning to make a board schematic with any electronical design application (Proteus, etc.).
It could be a better idea than make a Mega Mouse clone. Some old games that would be better playing with mouse don't support it, like Lemmings 1 (1991) because this peripheral didn't exists then. With this, you could emulate a mouse with a pad controller PIC which would be compatible with 100% Genesis games. But I don't know if it is possible.
I'm far from an expert, but a little googling suggests that you need to decap the chip and zap the part of the die that contains the write protect bit. I'm not sure how this would even work on a write-once chip like this. Or you could try to functionally reverse engineer what the chip is doing. With a basic device like this, it's probably pretty straightforward. Both of these options are over my head at the moment. I just thought I'd try reading it on the off chance it wasn't protected. I don't think there is enough of a demand for the end product to justify pursuing this further. There was barely enough initiative to get the Saturn mod chip cloned. I'm pretty sure you can thank BadAd84 and company for that.
You dont necessarily need the code inside the chip. You could reverse engineer it by building something that sits between the mouse and console and logs everything that is sent/received to a PC and then play a game that uses the mouse. If you can figure out all the data packets the mouse is sending back to the Genesis hardware, it should be possible to rip bits from an existing mouse (even an optical if you could find one with sufficiently-hackable guts) and build your own mouse from that.
That was said in the post above yours. Would be an interesting project, as you could upgrade it from a ball mouse to optical or laser.
