First steps towards emulating

blanka · Posted: Wed Oct 23, 2013 12:32 am Post subject: First steps towards emulating

Yesterday I visited a guy who works at TI chip design, and decaps chips for fun at home. We de-capped some of our favourite games' MCU's and here I posted some images:
www.2kboffun.com
We started with some Hitachi's, but they were a big bummer! The ROM section looks smooth as baby skin. No bits to see. It sucks because the Hitachi's are the best documented chips with instruction sets and all.

With Gakken Frogger and Tomy Tennis we had better luck especially when I found out the magic trick! So the Mitsubishi and NEC are better suitable for visible ROM extraction.

I want you handheld fans to do me a favour and check if you have any FUBAR games. I'm interested in these:

Gakken,Lansay,CGL Frogger,Jungler,Amidar (mitsubishi's)

And NEC's:
Bandai FL Crazy Climber
Epoch,Tandy Astro Command
Bandai Moon Alien
Bambino Superstar Football
Tomy Alien Attack
Tomy Alien Chase
Tomy Munchman/Grandstand Pac Man
Bambino Space Laser Fight
Bandai Vampire
Bandai Brique
Bandai Gun Professional
Grandstand Galaxy II (Epoch)
Epoch Crazy Monster (I.T.M.C)
Epoch Soccer (I.T.M.C)
Grandstand Caveman (Tomy,Tandy)
Scramble Tomy
Bandai FL Mobile Suit Gundam
Epoch Astro Thunder 7/Firefox 7
Epoch Space Galaxy II, Star Force

Please make sure your game is irrecoverable (not booting is usually easy fixed), I don't want you to kill precious games. If you have one, please send the chip (just cut the pins, we will do that too) to the address on www.retrospace.nl

blanka · Posted: Wed Oct 23, 2013 12:35 am Post subject:

If you ran into the problem of MCU's hidden UNDER the VFD: do me a favour and ship the whole board. We have good use for VFD's too, and cutting those off would be a pity. I can desolder them pretty easily.
I'm working on a generic driver board for VFD's, and the ultimate goal is to be able to run emulated coder to drive these.

Rik · Posted: Wed Oct 23, 2013 11:52 pm Post subject:

I've done something similar, sending some games to be decaped and analyzed, but I haven't heard back from the guy... Will have to get on him about that. I want to 'dump' the ROM contents of all the Microvision cartridges, and then the LCD driver chip for coding a perfect emulator for the Microvision... Not sure if it'll ever happen, but I want to try. Smile

I assume you've seen the Visual 6502? Those are the guys that have the games I'm talking about... [Edit- Haha, nevermind, saw your other post... Cool

)

Can you really not see anything on the Hitachi's? How is the ROM stored? There has to be something there. Assuming it's a mask ROM I suppose, you don't think it's actually PROM embedded in there, do you?

Can you send me a high-res picture of one of the ones you can make out the code on? I'm curious how much work it's going to be to 'hand dump' the ROM sections... Or maybe we could some kind of OCR code that would just do it from an image. Smile

I'll see if I have any dead games around. I also like the idea of a VFD adapter for an emulator, that's actually kind of cool... Smile

We could even re-write games if we felt like modifying them.

blanka · Posted: Thu Oct 24, 2013 12:27 am Post subject:

The Hitachi's might have PROM indeed. It looks a bit like this up close:
http://www.flickr.com/photos/6.....otostream/

What I'm doing is I'm putting the images in Photoshop and align them to the grid. Then I manually check if all dots are nice, and then I resample until I have a perfect B&W images with only black and white pixels representing 0 and 1. Then I want to store it in a 1 bit TIF/TGA so it is easy to process in every direction by the guy who's making the emulator.

blanka · Posted: Thu Oct 24, 2013 12:39 am Post subject:

This is my first attempt on the Frogger chip:

Note that the right part was very fuzzy (bad picture) so I will fix that soon, but it gives you an idea. With these little GIF images you also capture the exact layout of the original ROM.[/img]

blanka · Posted: Sat Oct 26, 2013 3:57 am Post subject:

I found an interesting read on Masking ROM techniques, and there was also implanted ROM which is almost imposible to read optically, only when you etch off the top layer!
So the focus is now on Mitsubishi/NEC chips. If you have any non-working game with those, send them in!

blanka · Posted: Thu Nov 14, 2013 11:55 am Post subject:

First ROM is complete. Next step: to emulate the 4-bit instructions.

Rik · Posted: Thu Nov 14, 2013 10:05 pm Post subject:

Disassemble it! I'd love to see the actual code... Cool

blanka · Posted: Mon Nov 18, 2013 12:17 am Post subject:

Rik:
I tried to do it on the Frogger and this is what I'm able to process out of it right now:
https://scontent-a-ams.xx.fbcdn.net/hphotos-prn2/1460262_423904441069961_778134631_n.png

This morning I extracted the Tomy Pro Tennis ROM and I'm going to process this one first, as the readout is probably 99.999% accurate, I can't say that with the Frogger.

I also managed to find the D552/3C instruction set with binary codes, so this one is easy to disassemble as well.

If any has wrecks with NEC chips (I'm also curious about Casio LCD games as these run on NEC most of the time), let me know!

blanka · Posted: Mon Nov 18, 2013 12:26 am Post subject:

Oh, and I can tell you now there is a difference between Tennis and Pro Tennis. The Tennis game has a 1024byte ROM, this one a 2048byte one, but only with 1072 bytes used. So 48 bytes extra WOOHOO! They must have put some crazy improved artificial intelligence in there.