Build-In-Game for Mega Drive

Hey there,

ArcadeTV from circuit-board.de got the idea to make a build in game for the Sega Mega Drive. ArcadeTV, srdwa and I, we started into development of the access logic, because the game should only start if the no cartridge and no MegaCD is running. During development we came across with replacing discrete logic with a PLC, so we were able to include functions like the TMSS disabler or a bankswitch for using multiple game in the internal rom without any extra software.
German logs can be found here: URL to cicuit-board.de
Due to a lack of time the development had stucked but is still in progress... I uploaded the current source we never tested so far ( ) to my GitHub repositories: URL to GitHub.
If you want to test it, do it on your own risk! Otherwise just watch out, what it becomes

 

This is a cool modification for the Mega Drive! I can imagine for those who mainly play one particular game that this can be quite convenient. Due to time constraints I never got around to get my Mega Drive jammafied, but this would definitely be a great addition

 

I need this in my life

 

Glad you brought it over here to us from your usual forum, thanks. I'll order a few and see how it all works out. Just need some more info about any trace cuts and if the PLD is a necessity for the board. What program or software suite (and programmer) did you use to program the PLD?

 

Nice project, thx for shareing it with us.
Maybe you open a sales thread with some of your projects?

 

There was a clone that immediately came to mind because they did something like that.

 

At the README you find the pinout of the PLD.
You have to cut at least the wire at B32 which indicates, that a catridge is present. The PLD accesses this flag at the ASIC to show that there is a 'virtual' cartridge.
You also have to cut the wire at B17 if you want to use the TMSS disabler (short the two jumpers for that at the PCB if and only if wire at B17 is cut).
I have in my notes, which ASIC pins corresponds to the needed pads. But my notes are deep within my desk, which is in my bedroom, where my newborn kid and wife are sleeping at the moment
However, keep in mind that I don't know whether it works so far or not. The reason why on picture above there is no PLD installed. I wanted to use a wired socket there to reprogram the PLD if needed.
As you see, the PLD is needed!!! It also controls the signalling for the internal Flashrom
I use the ATF16V8. It can be programmed using the Tl866CS/A aka MiniPro.
I decided to design the PCB for the SOIC package because it is comfortable to solder. However, for my first tests I use the DIP package
http://www.digikey.de/product-detail/de/ATF16V8BQL-15SU/ATF16V8BQL-15SU-ND/1008419
http://www.digikey.de/product-detail/de/ATF16V8BQL-15PU/ATF16V8BQL-15PU-ND/1008412

This will be my last project at all. I decided not to sell my projects professionally due to the lack of time. All parts I do sell are just overhead of productions for my self. However, I will see what I do have left in my basement and then I may open a thread... maybe

 

your last project??? whyyyyyyyyyyy
interested in this board to install in my md1 , just like all your other stuff this is really really cool

 

This is amazing! Where can I get one? Also, will the TMSS disabler work with normal cartridges?

 

If borti has no objection I uploaded the gerbers to OSHPark and also added info on the caps and IC's needed on the back side as well as label the jumpers for easier Identification.
https://oshpark.com/shared_projects/YpHcyJhv

Question though about the TMSS disabling, does it work on the Model 2 systems? and do both Jumpers need to be closed?

 

Thanks for this. I'll have to get everything later this year or sometime in the beginning of next year and try it out.

 

@borti4938
just like keropi, i'm really sad you'll stop your so useful work.
thank you for your NESIRG and SNES project :]

 

Better: my last new project I will try to support as good as poosible my old one (and improve the structures)...

No objections Just keep in mind, that you might that the space below the mainboard is very tight - especially in MD2. My first prototyp boards has a thickness of 0.6mm instaed of 1.6mm!

The TMSS disabling works in the same way as described here: http://assemblergames.com/l/threads/md-genny-auto-switching-tmss-bypass-mod.19781/
Both jumpers has to be closed: the left one connects the PLD with B17, where the connection from the ASIC has to be cutted; the right one enables the TMMS disabler. For disabling the TMMS mod after cutting the wire at B17 one has to do open up just the right jumper.
However, the ASIC side of the wire at B17 goes to the pad '/CS' in any case. For v1.5 I wanted to add a jumper such that one may only close the jumper iff TMSS disabler is not wanted at all...

I see that this thread is quite interesting to write some kind of an FAQ and for documentation on GitHub.

 

This is really nice. It would be even cooler if this method could be used to install an EverDrive

 

You can install an everdrive in the console already but it would mean you can't use carts anymore. Simply solder the pins on the cart to the cart slot pins on the underside of the motherboard. Then mount the everdrive board somewhere in the console. Desoldering the cart slot might make it easier and you would be able to get to the pins from the top side of the motherboard.

 

An automatically detected internal cartridge makes sense. Losing cart support is excessive outside specialized scenarios, too many gadgets and things won't work.

 

But that's not what I want at all. I use original games far more than I do my EverDrive. But if I could avoid having to keep that loose ED cartridge around, that would be nice

 

Ah ok. Installing the Everdrive like the normal games on borti4938's board would be awesome and better than my idea lol.

 

I like the idea of being able to have a small amount of "installed" games in an old console available to play whenever. I'd thought of that before in regards to the NES. Having an appealing menu to select games would make it nicer than any method using a switch of some kind which also makes it more practical for storing a larger number of games.

 

Yesterday, I finished my prototype of this project here Now I can play Sonic without having a cartridge inserted



During the next days I will update the GitHub source with PCB and new PLD code including some remarks, how the 'new' PLD code will work with PCB v1.4 (in case someone has such a PCB at home for testing)