So, today PayPal stopped locking away the money you’ve been paying me for GDEMU. Or rather, they will stop doing it, most of my account balance is still frozen and will be like that for weeks to come. Apparently it’s because I have too many unresolved issues with my customers – and so that you know, that number is zero, not a single issue has been filed. Still, zero is a bit too much. 100% customer satisfaction is just not cutting it these days.
PayPal also warned me that the lockdown might return, and listed a number of reasons for that which can basically be summed up as “because”. Well, it could be worse. I know people who had much less luck than me and got their account locked for good until they deliver blood of their firstborn, on a full moon. All of it.
The good news is I got the PCBs and started assembly of the second part of the run. Now this will probably take another 2-3 weeks to finish so if you’re near the end of the waiting list you will have to wait some more. But you will get the revised PCB with screw mount. This also goes for people who ordered 2 units but received only 1 so far.
Lastly, there were some questions in the comments about making GDEMU-like devices for other CD-ROM based systems that are old and start to fail – I’ve been thinking about that a lot lately and decided to investigate. This is all I can say for now 🙂
GDEMU 
A Sega Saturn CD-Emulator would be awesome! Apparently, someone in China has been giving it a go and the result is here: https://www.youtube.com/watch?v=6qcqzHBRssA
As you can see, the result is far from perfect, but my guess is that you can make this work 😉
This chinese device is not a CD-ROM drive replacement, infact it’s a cart that fit into the serial slot of the Saturn, I doubt it can run games since serial port has a low transfert rate.Here you can find a not finished project about a real Saturn CD-ROM replacement:
http://web.archive.org/web/20121103092509/http://www.crazynation.org/SEGA/Saturn/cd_tech.htm
I think it’s a good start since there are a lot of info about the interface (pinout, logic analyzing of signals, etc..)
Not to repeat always same things, Deunan, but don’t overstimate also FM-TOWNS machine (pc and consoles) , they are more popular of what we could think!I’m at your disposal for any info request about this machine.
Don’t understimate, I meant..)
I’m aware of that Saturn page, it’s some good info there but not without slight errors. And it’s not exactly complete either, I will need to run a lot of my own tests anyway. I think Saturn can be done without FPGA, which would make the project less complicated and cheaper.
As for FM Towns – I’ll admit my knowledge of this system is sketchy at best. Wikipedia says it uses single speed CD, is that the only model it had? Was that a SCSI drive or one of the early custom protocol that were typically connected to a sound card?
FM-TOWNS CD-ROM speed may vary from 1x of early models to 4X of the latest ones.
Here you can find some info about different CD-ROM models (japanese site):
http://hp.vector.co.jp/authors/VA018718/towns/tcdrom/tcdrom.htm
It’s not a SCSI drive (SCSI is used by HDD and external peripherals).
Regarding the interface, there is no pinout avilable.In the FM-TOWNS PC the built-in CD-ROM (usually a Matsushita EBP504) has a 40 pin connector and on its PCB there are some Technics (a.k.a. Panasonic and Matsushita) and Sharp ICs so maybe it has some in common with those early custom protocol like Panasonic MKE (even if MESS/MAME driver developer said me the commands set is different).
You can download some pictures I made from my FM-TOWNS FreshTV model:
http://www.mediafire.com/?s1d5qfuvr8vo858
As you can see from pictures, built-in CD-ROM had to be inserted in that riser card.This riser card has two IDC header on it, the 50 pin one on top is for SCSI HDD and the 40 pin on bottom is for built-in CD-ROM
Here is a partial schematics of its CD-ROM interface I drawn:
Click to access FM-TOWNS+II+FreshTV_CD-ROM+interface.pdf
Regarding software, all FM-TOWNS CDs can be perfectly read by PC so have the ISO9660 standard and can contain DATA, DATA+CD-DA and also XA I presume.
Hardware of FM-TOWNS consoles (Marty and Marty 2) is a designed a bit different, you can see some piture of the motherboard here:
http://nfggames.com/forum2/index.php?topic=2130.0
but since it’s derived from FM-TOWNS pc I think the interface is the same and also here if the CD-ROM unit goes bad you will not be able to boot software.
40-pin connector is either IDE (unlikely) or custom 8-bit protocol with many pins simply grounded. I’ve dealt with those before (in another project) so I have some idea, but that was years ago. The good news is AFAIR Linux kernel has some drivers for those now, could come in handy.
Thanks for the links, I’m going to read those materials when I have some free time.
Obviosuly the intercafe is not IDE but a custom one.As you can see for my schematics many pin are tied to ground and some to +5 and +12 v (
I downloaded it and yes, it looks very much like the Mitsumi / Matsushita kind of interface I worked with. I don’t think emulating those would be that much trouble unless there are games that somehow depend on the manual reading speed switching to work properly. But even that can be done.
FM Towns is not really “a target” right now but keep asking and I will get to it eventually 🙂
Hi Deunan, I’ve just finished to draw the FM-TOWNS CD-ROM schematics if you are still interested in, you can dowload then from here:
Click to access FM-TOWNS_II_FreshTV_CD-ROM_interface.pdf
A 3DO FZ1(or even a smelly fz10)CD-Rom emulator would be awesome. I know some other guy made one but he just wont sell them for some reason. If you make it, we will buy ;0)
Just for technical curiosity, what was the Mitsumi/Matsushita you worked with?If you find it useful, I can finish to drawn schematics.Since interface is similar, do you think a Panasonic MKE CD-ROM could be adapted in some way?Anyway, if you need real hardware, feel free to ask.
P.S.
What do you mean for “manual reading speed switching “?
I don’t remember and I no longer have the sources for that project on my HDD – but I certainly have backups somewhere. I still have one of the drives I used back then so I’ll dig it up and tell you.
Since there are a lot of custom chips there I will need to either find my old notes with pinouts or hook up logic analyzer anyway. Having a schematic where all the power supply pins are marked could help to cross-check my notes. Leave the rest simply marked as “data” and that’s it.
At least one of the drives I used back then was 2x speed but to actually get it to work at 2x you had to issue a command to switch speed. There was a choice of 1x, 2x and auto, and I don’t quite remember if auto was the default after power-on…
Yes, I wanted to use my logic analyzer too but didn’t find time to do it.Anywan my schematics already show where are the power pins, then I presume all other signals are the data and control bits.
I presume you have a Panasonic CR-5XX drive which need to be connected to a proprietary ISA card.This is its pinout (which is not the same as FM-TOWNS):
http://www.chiark.greenend.org.uk/~theom/electronics/panasoniccd.html
Oh, I remember that Panasonic – had one of these as well. The drive I have left is Mitsumi FX001D.
There is a video on Youtube about the Mitsumi FX001D:
ISA card is 16 bit though CD-ROM has 8 data lines?
I had a look inside also the Marty 2 console and hardware used is diferent than FM-TOWNS pc, there is a YM6063B – CD-ROM Interface IC
Besides, in FM-TOWNS pc there is the possibility of connecting SCSI external CD-ROM and using a thirdy-part software driver you can assign to this external unit the ‘Q’ drive letter which is the default of the built-in CD-ROM but sadly it’s not possible to boot from it.Anyway the sources of this driver are free and IMHO it’s worth to look at it since you can understand which are the CD BIOS calls and commands set.
I’m a bit hazy as to exact details but that particular drive is semi 16-bit. IIRC the commands and all reads except data were 8-bit, but the data transfers are using extra 8-bit to speed things up. I just took a quick look at the PCB and half the lines (every second one) are GND, and there’s ‘245 (the bi-dir low byte) and ‘244 (out only upper byte) connected to the interface.
The other drives were purely 8-bit I think but eh, it’s been so long ago…
I see.So there are strong similarities with the FM-TOWNS CD-ROM interface, same locations of GROUND pins, 74LS244 on data lines.On some ISA card I can see also some ICs with same package of the Hitachi HD6433248CP8 MCU used on FM-TOWNS, maybe they are a rebadged version.
So I guess it’s defitely an 8-bit interface.I think it will be quite straighforward (for who has the skills, obviously..) to study some replacement, perhaps only adapt one of these old CD-ROM, it would be enough.Obviously a not optical solution will be the perfect one.
PS2 would be ideal, even though we have HDD loading there’s still plenty of compatibility issues. A drive emulator would sort everything.
PS1 might be worth a look as I don’t have a lot of faith in the current PSIO project. For the amount of time they’ve been working on it there is very little news or working proof. It all seems very sketchy.
Except it was sent to an independent member of assemblergames and verified to be real…
That’d be fair enough if I said it didn’t exist in some form but, I didn’t.
@caiusfabricus What do you mean it cant run games? It runs games in various of the videos posted, even with sound.
@John Sheppard: You said very little proof or news. I wouldn’t call someone else testing it and verifying that it’s real, or the videos of it in action as “very little proof”.
Regardless, Deunan would have more buyers if he did some sort of EMU for the Sega Saturn or PS2. He could make one for PS1 as well and I’m sure it would still sell.
Deunan, in Sept of 2012 you said this about the GDEMU:
6) Other features?
Well, if it ever happens that I make tons of profit on these things, which I doubt, I might reconsider my stance on UI, USB host, and other things. But that would have to be a considerable amount of money to motivate me 🙂
Now it may be too early to tell, but do you think you would reconsider your stance on something like USB host? I was holding out for DCIO which is supposed to have HDD capabilities, but I will probably buy a GDEMU on your next run of them. I would love to see USB host enabled in the future, as I’m sure there are others who would too.
Haha, first of all, I think you overestimate how much money I’m making on this. While yes, I do have “positive cash flow”, most of it will cover expenses I already had developing each prototype, plus the original goal of paying for software upgrades that I need.
Second, GDEMU design is a compromise between cost, “time to market” and reliability. People always want more. The menu thing, more buttons, more LEDs, or LCDs even, USB host, USB PC uplink, SATA port, etc. There are projects out there promising those features. How many of them are completed yet? And lets not forget that adding a properly designed USB 2.0 port will require 4-layer PCB, external RAM chip to smooth out the latency of USB bulk transfers, and even that will probably not be enough for some games unless the buffer is many megabytes big. And then there are cheap USB pendrives with horrible, horrible random latency which people would try to use and blame GDEMU for not working properly. And I’m not even going to list the cons of adding a SATA chip…
There are already problems with some SD cards that don’t really play nice. Trust me, the way GDEMU is now is a very good compromise between project complexity (and thus cost) and compatilibity, plus ease of use. Adding more is possible but it’s nowhere as easy as some think. It’s not going to bring only good things, unless considerable time and money are spent on ironing out the new design.
Please, Deunan, don’t care too much about what people want or pretend and go straight on your way with your Dreamcast GD-EMU.From my own I’m not asking you to do something for me but I want to collaborate and share all info I have hoping this will help you ..if I only had yor knowledge and skills I would make myself a CD-EMU for FM-TOWNS (and also other systems) 🙂
Hi. I knew about this project just a week ago. If you’re considering about assembling new units, I’m your buyer. Thank you for your time.
Deunan, I have a quick question. I am on the preorder list for getting a GD-ROM emulator, but I am toward the end of the list. I’m a little concerned about missing the e-mail requesting payment or having my orderer delayed because PayPal decided to arbitrarily freeze your account again. Would it be okay if I just sent you the money now, rather than waiting until you have a unit ready to ship? I don’t have any doubts that you will be able to deliver, and I promise not to hassle or bother you in any way if there are further unforeseen delays. 😉
I’d rather not take money up front, I’ve recently learned it’s the easiest way to get PayPal lock your account. They don’t really need a reason to do that but that is very good excuse for them.
If we’re talking about drive emulators for other consoles my vote would be for Saturn and PC-Engine.
Agreed on both of those. PCE would be awesome.
I’d have to agree too on both counts
Well then, you people might be in for a nice surprise.
Don’t tease us like that! And thanks for your response above in regards to USB host. I was just asking if you had considered it, but I agree that GDEMU is good like it is now.
Maybe an universal CD-EMU? 😉
So i found out about your project way after the fact.. can’t even get on the pre-order list. If i promise not to complain, follow up about any bugs etc, can i get on your list to purchase one of these? I have a very technically savvy friend who has already received one from you. He would hook me up with the iso files look into the issues etc based upon his own experience. So no additional service from you would be required. How does someone like me (zero chance of ever being able to accomplish something like this myself so basically would be happy with whatever i do get to work) get a piece of the the action?
Sorry i’m all over the place. Thanks for replying to me on the other thread.
As far as talk of the Saturn emulator… well that would only double my enthusiasm to a rather scary level.