Mega CD

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cleeg
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Mega CD

Post by cleeg » January 9th, 2014, 8:38 am

This type of thing must be possible for the Mega CD? Who'd like to make me one then?

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Re: Mega CD

Post by Greg2600 » January 9th, 2014, 12:18 pm

Good luck on that one. The Sega/Mega CD does not use an IDE or similar interface to a drive. It reads CD's like an audio player does, requiring 2 second gaps between the tracks. You'd have to rewrite the entire CD Bios from scratch, which is probably in God awful assembly language. It's probably easier to emulate the SCD completely in FPGA and interface that right into the Genesis's expansion port than to simply replace the drive with something else like the PSIO or DCIO will do.

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Re: Mega CD

Post by Yuri » January 9th, 2014, 5:13 pm

actually it can be done, maybe easyer than psio & dcio. as old cd-based consoles dont ask much from cd-drive - just stream of data. for example psx cd-dsp also makes xa decoding, that's make it little harder to emulate... gd-drive send data very fast (12x speed). as i saw about mega-cd or similar consoles - it uses serial stream interface,

but another point - how much ppl wanna get such emu. and also depends on spare time and funds... as always

PS: i dont have MEGA-CD at all. so 1st what i need to say more - i need get it some where.

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Re: Mega CD

Post by SegaSonic91 » January 14th, 2014, 2:11 pm

As much as I love my Mega-CD and Wondermega, I would think that a Saturn and PC Engine version would be in much,much higher demand. Still, if some sort of "pre-order only/pay up front" M-CD unit was made available in the future, I would jump on it!

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Re: Mega CD

Post by RetroRepair » January 15th, 2014, 7:52 pm

I totally agree with all of that SegaSonic91

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Re: Mega CD

Post by Yuri » January 15th, 2014, 10:33 pm

unfortunatelly "pre-order" is almost near at release stage, but to get so far we need walk through prototypes, make many tests, research many questions.

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Re: Mega CD

Post by Yuri » January 15th, 2014, 10:40 pm

maybe Sega-CD is more lucky console, and maybe cd-emu can be done by using only mcu (ARM).
but to get console (or couple) for reseach is not easy today. i think it is quite rare? another question - is images for this console easy to get from i-net? or we need make dump/copy of original cd?

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Re: Mega CD

Post by cleeg » January 16th, 2014, 2:52 am

Saturn, Defo. I have one and would love something like this. Wondermega? I looked at one of those too, a bit out of my league, so I settled for a CDX. Shame, I loved those flashing lights!

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Re: Mega CD

Post by SegaSonic91 » January 16th, 2014, 5:22 am

cybdyn wrote:maybe Sega-CD is more lucky console, and maybe cd-emu can be done by using only mcu (ARM).
but to get console (or couple) for reseach is not easy today. i think it is quite rare? another question - is images for this console easy to get from i-net? or we need make dump/copy of original cd?
There are plenty of Mega-CD ISOs around on the net. But I am not sure if there are "proper" releases like the redump project for PS1 and Saturn etc. I personally own an almost full set of Japanese games as well as PAL and SEGA-CD games if proper 1:1 dumps are needed. I have my original PAL M-CD that I bought back on 31 March '93 packed away safely, that cost me $699 back then. My 14 year old self worked and saved for a looooong long time for that system and boy did I love it. In fact, 2 of my 3 equal favourite games ever are M-CD games :D. I will never get over the feeling that the M-CD could have been something special if only SEGA had listened to SoA (hard to believe I am saying that, ha!) added more graphics chips to boost the colour/sprites/background layers to go along with the grossly underused PCM sound chip and amazing near system-16 scalling/rotation chip that was apparently too hard for anyone but CORE to use. Actually SUPPORTING the system could have helped as well! Ahh, I slipped into one of my rants, sorry! Back to the topic ...

The systems are not exactly "rare", but they are usually not cheap which is a problem. I saw 2 or 3 big lots of broken SEGA-CDs on ebay at the tonight but shipping outside of the US would be a huge concern I would imagine. Just how broken they are could also be a concern.
cleeg wrote:Saturn, Defo. I have one and would love something like this. Wondermega? I looked at one of those too, a bit out of my league, so I settled for a CDX. Shame, I loved those flashing lights!
I love my Wondermega! It is a thing of beauty. I was lucky enough to score it off yahoo while I was living in Japan in 2006. I think it was around ¥17,000 with a rather large collection of mint MD games and possibly a few M-CDs. It even had some really good games which was a surprise. It was unboxed, in pretty good condition, but did come with the Victor pad and Wondermega collection CD. There was a big shop near my uni that had a boxed, mint condition SEGA model Wondermega for ¥39,000. I swore I would buy it before I went home, or when I went back to visit the following year, but stupidly I never did. Having to save ¥70,000 for the PS3 in 2006 didn't help. I would love to have a boxed, mint Victor and SEGA Wondermega and same for a WM MkII, but the prices they go for these days say that will never happen. Maybe if I win the lottery one day :D

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Re: Mega CD

Post by Yuri » January 16th, 2014, 7:12 pm

http://i020.radikal.ru/1401/e1/99c9afb9c58d.png

Image

i see M-CD has similar interface (like PSIO) , it's "HOST<>CD-ASIC".
another way is interconnection between CD-SUBCPU and CD-ASIC.
actually, M-CD plugging to Sega as some kind "smart cartridge" w/ access to CD.
...if i can get one (M-CD), i can say more, maybe in future...

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Re: Mega CD

Post by Yuri » January 17th, 2014, 12:43 am

..unfortunatelly, M-CD inside is like "micro console" , with it's own main CPU Motorolla M68000. emulation of all device is not easy.
maybe only if we do emulation of "cd" side of the device.

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Re: Mega CD

Post by SegaSonic91 » January 17th, 2014, 3:24 am

So the Mega-CD's processor, PCM sound chip and scaling/rotation chip needs to be emulated in some way too? Yes, it was not *just* a CD ROM attachment like the PC Engine CD system. It had its own Motorola 68000 prcessor which was twice as fast as the MD's chip as well as a high quality PCM chip and the very powerful scaling chip. The Mega CD was a very powerful system, it's just a shame that only a handful of games prove that fact. Too many companies saw the MegaCD as a Mega Drive with more memory. If only it had a new graphics chip for higher colour....

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Re: Mega CD

Post by cleeg » January 17th, 2014, 4:42 am

I always thought the thing that let the Mega CD down was the lack of colours. The effects were on par with SNES stuff, it often just looked a little more drab or a little too psychedelic in some cases. Still cool though.

The Saturn idea is intriguing though. I'm dreading the day my lasers die, I'll have to (ugh) emulate full time. SSF is pretty god though.

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Re: Mega CD

Post by Yuri » January 17th, 2014, 7:01 am

M-CD is complex device inside, i dont get why it uses such scheme. maybe M-CD can do much more then just load data from CD.
I mean, we can emulate only part of cd-drive, so main MCU thinks it works with cd. but disadvantage is we need have M-CD (at least we can use broken one )

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Re: Mega CD

Post by Greg2600 » January 17th, 2014, 1:04 pm

Most games really didn't utilize anything on the CD, they were almost exact to the Genesis version. Hardware-wise, it provide CD audio, Full motion video (in only 32 colors), and scaling/rotating "Mode 7" types of graphics. I don't think I'd waste time on it. PS1 and Dreamcast have a MUCH larger "install" base. To me the holy grail of flash-carting would be the ultra-complicated Sega Saturn!

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Re: Mega CD

Post by SegaSonic91 » January 18th, 2014, 12:03 am

cybdyn wrote:M-CD is complex device inside, i dont get why it uses such scheme. maybe M-CD can do much more then just load data from CD.
I mean, we can emulate only part of cd-drive, so main MCU thinks it works with cd. but disadvantage is we need have M-CD (at least we can use broken one )
HAHA! When did SEGA do ANYTHING simply post Mega Drive! They made amazing "ahead of its time" hardware. So ahead of its time that nobody cared to use it.


Spot on cleeg, colour would have made the MCD amazing. I would love to go back in time and stop Night Trap from ever being made. I loved the game at the time, but it really fucked the image of the system in the US when more and more shitty Night Trap wannabe games kept coming out. It turned fans off the system and in turn third parties from making games for it.

I also agree with the Saturn idea though, far cheaper to obtain hardware and much bigger interest for the product. Same with the PC Engine. There are millions of blind PCE fanboys in the world afterall.

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Re: Mega CD

Post by Tranqex » February 1st, 2014, 9:04 am

Mega CD would be good because we can already have standard and 32x carts running from SD cards and emulating Mega CD would mean all Mega Drive/Genesis games would be able to run from SD cards instead of just the cart games.
I would still rather see DCIO before Mega CD emulation though. I am worried my Dreamcast laser will die some day soon :(

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Re: Mega CD

Post by RetroRepair » February 12th, 2014, 10:16 am

Personally I think Sonic CD and FinalFight are worth the effort alone. CD drives are much less reliable than roms so I doubt it'd be that long before they can't be played on original hardware anymore.

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Re: Mega CD

Post by SegaSonic91 » February 23rd, 2014, 2:39 am

Having just purchased a Japanese Mega-CD 1 that does not read discs and subsequently having read about the horribly common laser and/or CD mech failure, a PSIO type device for the MCD sounds 100 times better than before. If it isn't laser or CD mech failure, it is very very common for the CAPs to leak and fry the board. The idea about using the system and only emulating the CD-ROM itself, sounds perfect. Most of the time the only problem with broken units is lack of being able to read discs.

My original launch PAL MCD1 has been packed away in its box for about 15 years by now. I am so afraid that it'll be dead now. I will be very sad if a day comes that I will no longer be able to play Lunar TSS & EB, Urusei Yatsura: Dear My Friends, 3X3 EYES, Final Fight CD, Silpheed, Bari-Arm and so many other MCD games I love, on a real system. I would gladly donate a system for research if the damn things were not so rare and pricey these days. Mega-CD 2's are more reliable but are still prone to failure. I think a MCD2 would be best for research. There is already region free BIOSes out there so there would be no problem in that area.

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Re: Mega CD

Post by lovewiibrew » February 24th, 2014, 6:23 pm

Emulation is almost perfect with the Sega Genesis and Sega-CD, I would think it would be a waste of time to make a Sega CD IO. Imo, efforts are better spent on the Sega Saturn and Sega Dreamcast.

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