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Megadrive was always the answer
Posted: Sat Aug 31, 2019 11:43 pm
by danibus
Sega Megadrive/Genesis was designed to be connected with several peripherals and expand their capabilities. Is it possible today to expand its capabilities?
Can we create an add-on that meets these requirements?
- Easy to use. Plug’n’Play. No manual welds.
- Easy to program. Scene friendly.
I have a proposal.
This is a proposal to make a new-old hardware expansion for megadrive.
Thanks for reading and comment here what do you think about.
Re: Megadrive was always the answer
Posted: Sun Sep 01, 2019 12:13 am
by djcouchycouch
That's crazy and awesome
Re: Megadrive was always the answer
Posted: Sun Sep 01, 2019 7:12 am
by cero
Well yes, GOAC + output mixer + glue would be cheap to make, however the total market for any expansion is low. Even for official Sega ones.
Re: Megadrive was always the answer
Posted: Tue Sep 03, 2019 11:52 pm
by 8bitwizard
What's the point in making anything using CD now when you can use an SD card instead?
Stick an ARM in there to handle loading from the SD card, and maybe a few other things like play audio files from the SD card (like playing red book audio from a CD) and writing game saves to the SD card. What you've got is just way too much new hardware to make from scratch, then you have to get people to develop for it, when the only audience is people who first had to buy the franken-mod.
I'd just rather have something simple that can load ROMs quickly to make development and debugging easier, and cram it with RAM. Some ARM chips have an Ethernet port, that could be used to load a game via FTP or TFTP. The most you would have to do is link the ROMs to a different base address. Maybe 68k cartridge space could be mapped to RAM that is read-only on the 68k side, then you could run vanilla game images.
I even have a few 62-pin edge connectors set aside to do something like this. (It's a backplane from a Cybex Commander 4XP KVM. I still need to desolder them, but I have hot air tools now.)
Re: Megadrive was always the answer
Posted: Wed Sep 04, 2019 12:40 am
by Sik
Um, that first paragraph basically described the Mega SD…
Re: Megadrive was always the answer
Posted: Wed Sep 04, 2019 6:59 am
by cero
And the second UMDK and Mega Everdrive x7.
Re: Megadrive was always the answer
Posted: Wed Sep 04, 2019 9:56 pm
by danibus
8bitwizard wrote: ↑Tue Sep 03, 2019 11:52 pm
What's the point in making anything using CD now when you can use an SD card instead?
Stick an ARM in there to handle loading from the SD card, and maybe a few other things like play audio files from the SD card (like playing red book audio from a CD) and writing game saves to the SD card. What you've got is just way too much new hardware to make from scratch, then you have to get people to develop for it, when the only audience is people who first had to buy the franken-mod.
I'd just rather have something simple that can load ROMs quickly to make development and debugging easier, and cram it with RAM. Some ARM chips have an Ethernet port, that could be used to load a game via FTP or TFTP. The most you would have to do is link the ROMs to a different base address. Maybe 68k cartridge space could be mapped to RAM that is read-only on the 68k side, then you could run vanilla game images.
I even have a few 62-pin edge connectors set aside to do something like this. (It's a backplane from a Cybex Commander 4XP KVM. I still need to desolder them, but I have hot air tools now.)
Not a monster... just another megadrive! You can make a game as now.
Different thing is to add a FTP connection, this is only for develop, and mass users won't pay for this.
Still, maybe you can use MegaWifi to send roms to megadrive.
MegaWifi is a
brand new cartridge, made by doragasu, first game using it will be 1985 World Cup, a footbal game.
https://twitter.com/octopusjig/status/1 ... 15136?s=20
Re: Megadrive was always the answer
Posted: Thu Sep 05, 2019 1:27 pm
by Sik
cero wrote: ↑Wed Sep 04, 2019 6:59 am
And the second UMDK and Mega Everdrive x7.
I don't recall any of the Mega Everdrives having an ARM CPU inside them.
Re: Megadrive was always the answer
Posted: Thu Sep 05, 2019 5:31 pm
by cero
"load ROMs quickly for development and debugging" -> both have an usb connection for that. ARM is just a detail.
Re: Megadrive was always the answer
Posted: Thu Sep 05, 2019 5:49 pm
by Sik
Well, when you're talking about making an add-on to improve the console, you probably want to throw the coprocessors into the mix (especially if you can use them to do something like the 3D in Virtua Racing). So I'd say it's not just a detail.
For what's worth it, I think an extended Mega Drive with the improvements built-in (probably a FPGA-based clone) would likely fare better than a standalone add-on.
Re: Megadrive was always the answer
Posted: Thu Sep 05, 2019 6:14 pm
by danibus
Easy. Can an emulator be altered (beast) to launch 2 instances an mix video output?
Then we can make a proof of concept, without making new hardware.
Re: Megadrive was always the answer
Posted: Fri Sep 06, 2019 1:50 pm
by TmEE co.(TM)
I have already explored this sort of stuff, the hardware part is actually easy and not a huge challenge, but it will be incredibly difficult to keep the costs sane even when I used cheapest parts and nobody will pay price of a modern game console for another 32X essentially, which will only ever see a smal handful of games and on top of it no actual "AAA" games that would really make it worth having. Even if cost can be only 100€ for the entire thing rather than double or even beyond, there will still be too little software to make it worthwhile.
Re: Megadrive was always the answer
Posted: Fri Sep 06, 2019 9:07 pm
by danibus
TmEE co.(TM) wrote: ↑Fri Sep 06, 2019 1:50 pm
I have already explored this sort of stuff, the hardware part is actually easy and not a huge challenge, but it will be incredibly difficult to keep the costs sane even when I used cheapest parts and nobody will pay price of a modern game console for another 32X essentially, which will only ever see a smal handful of games and on top of it no actual "AAA" games that would really make it worth having. Even if cost can be only 100€ for the entire thing rather than double or even beyond, there will still be too little software to make it worthwhile.
Did you check about FPGAs or GOACs?
FPGA without sound, Yamahas are not well supported right now
Re: Megadrive was always the answer
Posted: Fri Sep 06, 2019 10:58 pm
by TmEE co.(TM)
FPGAs are the only solution, and stuff where you can fit substantial amount of things are easily 50€ a chip (but some simpler stuff can be done with the cheap 20€ chips), and you still need various other parts such as DACs, memories, connectors and also plastic, assembly and distribution. What is your target price ? Also there was no mention of actual capabilities of the expanded side so I'm not sure what sort of logic resources are needed to realize them.
Re: Megadrive was always the answer
Posted: Sat Sep 07, 2019 4:37 am
by Sik
TmEE co.(TM) wrote: ↑Fri Sep 06, 2019 10:58 pm
Also there was no mention of actual capabilities of the expanded side so I'm not sure what sort of logic resources are needed to realize them.
Seems to be literally two Mega Drives glued together.
But yeah, also don't forget the extra RAM, since you aren't going to fit everything into the FPGA (even the larger ones are quite strapped on that end), which in turn can also make pin management hell… not to mention the cartridge slot itself already eating a lot. Which means you'll end up throwing in yet more support chips just to act as multiplexers. Oof. It looks like the only way to make a decent clone at a sub-$100 price is to risk it and attempt to turn it into an ASIC. Which means being willing to try to sell lots of units.
Now mind, with the retro collector craze going on, maybe in a couple of years an expensive overengineered FPGA clone will be cheaper than the original hardware :O)