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Sega Mega Play reprogrammable flash cartridge

TulioAdriano

TulioAdriano

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Hi all.

I recently came into possession of a Mega Play board, but I didn't have the games I wanted on it (i.e.: Streets of Rage II). So I decided to make my own flash cartridge.

photo_2023-05-30_10-28-25.jpg


This cartridge can be reprogrammed using a USB cable. It's not a multi, and it's not an EverDrive (i.e.: reads from SD). The main issue is that the Mega Play does not have a reset signal mapped to the cartridge slots, so a cartridge cannot be reprogrammed in place like you can do on Mega Drive/Genesis.

Anyway, since I made this, I'm curious if there's interest from other people to use such cartridges. I'm not looking into making money on those, just on covering the costs and the R&D associated with it. Price is $85 per cartridge. You can get one and reprogram whenever you want to change the game, or you can get many and program one game on each... that's what I did.

I'm also planning on getting some Mega Drive cartridge shells so if there's interest in that as well, let me know.

For now I'm just gauging the interest. If there are enough units wanted (i.e.: 10+) I can potentially get lower prices from the PCB fab.

If you're interest please reply with a note of how many you'd want and if you'd want shell or not. 😁👍
 
I was interested until I saw the price of Mega Play boards on eBay, who knew.

I might still be in for one anyway.
 
This is awesome, but yeah, I checked ebay prices and damn! lol. I have never seen a mega cab in person though.
 
Blio Seri said:
@TulioAdriano very nice repros.
Could you adapt the design to make it a multi cart? Even with dipswitch, that would be good enough.
IMHO having a flash cart that can only store 1 game isn't that useful, and people (like me) probably prefer to have one cart dedicated to each game. That's what I've done using the following design:
https://www.tindie.com/products/caiusarcade/sega-mega-play-reproduction-cart-blank-board/
Just 2 EPROMs to program per game.
Click to expand...
I know nothing about this hardware but if a reset signal to the cart is all that’s needed, it seems there are some unused pads on the cart, Although i’m not sure of the onboard connector. If there are any unpopulated positions I’d think a jumper can be routed to an unused position on the connector to a reset point on the motherboard where a multi cart would be able to accept it.
Maybe different carts use different pinouts?
If there are any that are never used it seems simple enough to route a reset signal.
 
Thanks to everyone for the kind words. I have my own rant about how expensive the MP related stuff is on another thread in this forum.

jamesv833 said:
I know nothing about this hardware but if a reset signal to the cart is all that’s needed, it seems there are some unused pads on the cart, Although i’m not sure of the onboard connector. If there are any unpopulated positions I’d think a jumper can be routed to an unused position on the connector to a reset point on the motherboard where a multi cart would be able to accept it.
Maybe different carts use different pinouts?
If there are any that are never used it seems simple enough to route a reset signal.
Click to expand...
The reset signal is the main issue when it comes to a cart that self programs from a SD, etc.

Blio Seri said:
@TulioAdriano very nice repros.
Could you adapt the design to make it a multi cart? Even with dipswitch, that would be good enough.
IMHO having a flash cart that can only store 1 game isn't that useful, and people (like me) probably prefer to have one cart dedicated to each game. That's what I've done using the following design:
https://www.tindie.com/products/caiusarcade/sega-mega-play-reproduction-cart-blank-board/
Just 2 EPROMs to program per game.
Click to expand...
Yeah I get it. A dip switch solution would work without it, it'd be more like the STV cart, which would have all ROMs programmed from the start and you just flip the switch to remap the address lines to where the game you want to play is stored at. I just did this as a learning experience and because I thought I was going to make a single cart, and then turned out having made 5 of them, so then what the heck, I just programmed one game to each.

I know of those reproboards, but having the ability to swap games whenever I want is really what I was after, and with the EPROMs it would be a pain to do since the EPROMs need to be UV erased, and there isn't enough space for a slot inside the cartridge shell, so they would need to be desoldered, etc. or maybe I'd have to buy a large UV eraser... anyway, this solution was the most handy to me. Plug USB, update game, play game. :D
 
Great work TulioAdriano!

Just wondering, did anyone ever make a Megadrive/Genesis to Megaplay adapter? Just like there is one for Megatech. I know that years ago Apocalypse was experimenting with one. I remember it also required a hacked bios.
 
With this flash cartridge you can load Mega Drive ROMs directly to it and they do boot without anything special. However, they cannot read any input from the system because it has the inputs mapped differently. So without some rom hack they wouldn't work on a Mega Play as it is different than the Mega Tech.

I have been poking around ROM hacking a game to run on Mega Play, and if I find out how it works, I'll publish my findings in my blog so that other people can do it as well.
 
Great! Just adding Apocalypse his research to this thread as his blog is no longer available.

24 Jan 2018​

Sega Mega-Tech & Mega-Play hack​


Both systems are based on the Sega Megadrive console.
Here's a quick article about my finds on these systems.

1) Sega Mega-Tech

1.1) Cartridges
They contain 2 ROMs :
- One is the game itself. It can be a Megadrive ROM or Master System ROM.
- The second contains simply the name of the game to be displayed on the upper screen

1.2) Functionalities
Motherboard can hold up to 8 cartridges.
Player buy time rather than credits.

1.3) Compatibility
The only thing that forbids you to play Megadrive or Master System games on a Mega-Tech motherboard is the difference of pinout. With an adapter they play fine.
Region can be changed via dipswitches.

On the other side Mega-Tech games can be played on either the Megadrive or the Master System (depending of their origin) with an adapter.

2) Sega Mega-Play

2.1) Cartridges
They contain 2 ROMs :
- One is the game itself. It's a modified Megadrive ROM.
- The second contains instructions on how to play the game.

2.2) Functionalities
Motherboard can hold up to 4 cartridges.
Player buy credits.
Games are generally shorter (less levels) than their Megadrive counterparts, and harder (less lives, less time).

2.3) Compatibility
First you'll need an adapter to play Megadrive games on the Mega-Play.
However with the stock BIOS it displays an error message on the foreground:

0001.png


0002.png


I modified the BIOS to disable that.

Mega-Play games still plays fine with the modified BIOS so no need to swap it every time.
Region can be changed via dipswitches.

On the other side Mega-Play games can be played on the Megadrive with an adapter and a bit of hackery to disable inter-CPU exchanges and force credits.

Here's the link to Sonic The Hedgehog I've hacked to be played on the Megadrive:
https://drive.google.com/open?id=0B3HXfvdQ0w7QaXNENTVoYWY0bTA
It's a quick and dirty job, just leave the intro play and when level 1 starts it's up to you. Lives are almost unlimited.
Differences with the Megadrive version are:
- no Sega logo on start-up, no "Segaaaaaa" voice sample
- no select round or debug mode (present but disabled)
- game in Time Attack mode, time goes backward with for example 50s allowed to clear Green Hill Zone 1
- only 4 zones + final zone in the following order: Green Hill Zone, Spring Yard Zone, Star Light Zone, Scrap Brain Zone and Final Zone
- no bonus stage despite the fact the big ring is present, thus impossible to get chaos emeraulds
- based on the Japanese version with clouds moving on a different layer, blurry effect when in water, etc.
- high scores table present

All zones are present but some have been disabled. However you can enter them with a hack:

0003.png


0005.png


As they weren't meant to be playable in Time Attack mode time starts from 0 so you instantly die:

0002.png


But are playable with a time hack:


0004.png





Publié par Apocalypse à 08:21
Click to expand...
 
I've ran into that thread a while ago. Unfortunately nobody has the modified BIOS and the link does not allow download, so I can't really test what it does. For all I know, it may just suppress the "Slot 1 cartridge not used" error, and he may have not tested if the game can be played (i.e.: react to inputs).

If by some miracle somebody has this BIOS, do let me know so I can dig further into this.
 
I'd actually be really interested in a set of these. I recently acquired a mega play and would be cool to have the set.

Do you happen to know if there is a way to put any genesis/md game on these and get them to work on the mp?
 
Koala_Koa said:
I'd actually be really interested in a set of these. I recently acquired a mega play and would be cool to have the set.

Do you happen to know if there is a way to put any genesis/md game on these and get them to work on the mp?
Click to expand...
I've tried doing that, and the game boots. However it does not accept any input from the Mega Play. I believe to make them work a ROM hack would be needed. If we're lucky, perhaps a BIOS hack could work for MD games. We miss you, @Apocalypse.

If you want me to make you some cartridges, just ping me on PM so we can discuss it. :)
 
Hmm, a rom hack for the mega play would be super niche but amazing at the same time. XD are there people in the community with the capability to do so? Be happy to send my board out for tinkering to get it done and compensate the individual.
 
A bios hack to allow for osd game select would be theroetically possible no? The megaplay multi cart!

On the meantime could i order several of the repro cart shells please?
 
Monstermug said:
A bios hack to allow for osd game select would be theroetically possible no? The megaplay multi cart!

On the meantime could i order several of the repro cart shells please?
Click to expand...
Yep, I'm about to order some shells and labels for myself, hit me on PM and I may be able to include what you need in the same order.

About the multicart, Blio and I had a conversation a few messages above about that. Depending on the kind of solution it can be more or less involved. I personally wanted an automated solution that does not involve modifying the board. But since there's no reset signal from the cartridge, an everdrive-like solution is out of the question. It would either need a board mod, or the cart would have to be dip-switch based.

Koala_Koa said:
Hmm, a rom hack for the mega play would be super niche but amazing at the same time. XD are there people in the community with the capability to do so? Be happy to send my board out for tinkering to get it done and compensate the individual.
Click to expand...
I'll reach out to my network of 68K gurus, maybe someone is interested?
 
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TulioAdriano said:
Yep, I'm about to order some shells and labels for myself, hit me on PM and I may be able to include what you need in the same order.

About the multicart, Blio and I had a conversation a few messages above about that. Depending on the kind of solution it can be more or less involved. I personally wanted an automated solution that does not involve modifying the board. But since there's no reset signal from the cartridge, an everdrive-like solution is out of the question. It would either need a board mod, or the cart would have to be dip-switch based.


I'll reach out to my network of 68K gurus, maybe someone is interested?
Click to expand...
I am not against installing something like a unibios but for the megaplay or soldering a chip to get past the security.
 
Could you not use manual switches to change the games? Sorry ive not kept up to date with this project. Also maybe u could wire up 3 more edge connectors so that all slots are populated to switch games? So have four on instead of just the one? Just a suggestion though. Theoretically possible?
 
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