Anyone got any info on this unit for the MD? Picture from: http://home.clara.net/robwebb/data/smdvr-cd.htm Got one today. Audio discs work Nothing else so far... PCB scan: High resolution: http://img239.imageshack.us/img239/7489/almavrcdux2.jpg IC-list: U1 - HD74HC245P U2 - HD74HC245P U3 - HD74HC374P U4 - T71C17400AJ - (4M x 4 FPM - 16Mbit) U5 - T71C17400AJ - (4M x 4 FPM - 16Mbit) U7 - HD74HC04P U8 - TC551001AFL-70L (128k x 8 SRAM) U9 - 27C1000 (BIOS) U10 - HD74HC245P U11 - HD74HC245P U12 - PC74HC157P U13 - PC74HC157P U14 - Xilinx XC7354 (some EPLD) Anyone seen this unit in action? To me it looks like a copier with 32Mbit for the MD with CDROM. Tried to put roms in various formats in the root directory of a MSDOS compatible CD-R. Didn't work. Think I'll dump the BIOS and see if I can figure anything out... CF
I had a Super Wildcard V64 a few years ago. The CDROM was so old, it couldn't read standard CD-Rs. I had to use an old Verbatim CD-R from 1999 which I had to burn on an even older SCSI CD-Writer from 1996 in SingleSpeed. It hasn't worked with my standard CD-Writer. Sounds crazy, but I learned a lot from my Wildcard issue: Some old CD drives can only read those old CD-Rs with a dark-blue bottom. Unfortunately those CD-Rs aren't available this time and you need a CD-Writer from that time for best results. Another reason could be the CD format. Don't burn Joilet, just MODE-1. Put only a few files on the CD. Maybe the unit cannot read more than 100 files or so. Before you do so, try to use another CD-ROM. Unfortunately that wasn't possible with my Wildcard V64. Update: The Wildcard V64 needs a index file and a special file format and naming convention. Maybe there is something similar for your unit?
Great Any picture of the displayed picture on tv? Any crazy cd player screen? Looking to your PCB, it don't appear to be much stuff... Seems pretty good designed stuff
Thanks for good advice mdmx! The VR-CD uses an old MKE drive just like the CD7 I think it reads my CD-Rs though. Just inserted a CD-R with audio, and that worked. No spinning sounds or anything coming from the drive.... I think you are onto something. Will dump the ROM/BIOS. Looks like I am going to have to make an adapter for my EPROM-programmer real quick (since the 27c1000 have pin 2 and pin 24 switched). Hopefully the ROM will reveal a bit more about what that is going on... BTW: If you remember any details on how the Wildcard 64 worked (index file, naming convention etc.), or have some files with info, I would be very interested TTYL! CF Update: Turn out it does not have a MKE drive. It has a CR-572-B drive, which is a normal IDE CDROM.
Yeah, there is a CD player screen, but it's not very original. Will post some screenshots as soon as I get the initial research done CF
There is a tool available called GameList V2 which creates the index file. I still have the software an some useful FAQs about the Wildcard. But it's too much text to post it here. here are some photos about the wildcard cdrom and os menu: btw, if you are interested in a Wildcard V64 with CD-ROM, I can send you the nickname of the guy who bought my unit.
To find out as much as possible about the VR-CD, the plan was/is to load the copier's BIOS ROM into IDA like a MD ROM and check it out (I use Kaneda's script). But the binary image I dumped doesn't look good. Left: Alma VR-CD BIOS - bad dump (?) Right: Normal game ROM As you can see the BIOS seem to have the stack at 0xE0CFFE which is out of the normal RAM range I believe. The header (0x100-0x1FF) looks crazy too, with TMSS code in the middle of it. This can not be correct. I must have done something wrong, or the BIOS is addressed by the VR-CD hardware in some crazy way... Some strings in the BIOS: 07151996 GAMARS CD-ROM BIOS Creative Voice File - the VR-CD says "Alma" at startup Now <%04X> No Sense !! Recovered Error !! Not Ready !! Medium Error !! Hardware Error !! Illegal Request !! Unit Attention !! Data Protect !! Aborted Command !! Miscompare !! Reserved !! TotalFile=%d [%s] [%03d] File name -> %s Got the system hooked up with a RGB SCART right now. Will post some good screenshots as soon as I find my AV RCA-cable which I can capture from more easily... If anyone got some tips or ideas on the BIOS dump and what I am doing wrong, that would be awesome... CF
"As you can see the BIOS seems to have the stack at 0xE0CFFE which is out of the normal RAM range I believe. The header (0x100-0x1FF) looks crazy too, with TMSS code in the middle of it. This can not be correct. I must have done something wrong, or the BIOS is addressed by the VR-CD hardware in some crazy way..." Well, it could be possible that this code is correct... The system can hyjack the megadrive memory map creating new ram locations...
Thanks Fonzie! Didn't know that. Still looks very strange. What do you think about the header? It has the TMSS complience code in the middle of the header: ROM:0000017A move.b ($A10001).l,d0 ROM:00000180 andi.b #$F,d0 ROM:00000184 beq.s loc_18E ROM:00000186 move.l #'SEGA',$2F00(a1) ..and the header starts with " EGA" instead of "SEGA". The other fields looks strange or incorrect too. Maybe most of the header is somehow overwritten with code from another place in the ROM when I dump it... CF
Yeah, the header can contain any type of data, no worries, only the SEGA at 0x180 matters for the TMSS. I think your code starts at 0x5594, you should take a look there. And yes, maybe the system have a wierd mirroring system... but it would be bad luck ;P
You are right again Fonzie Thanks! The dump seem to be OK. I wrote the dump back onto a blank 27c1000 EPROM. The VR-CD booted without any problems I have been disassembling the dump for a couple of hours now, and the layout seem to be: - interrupt table - crazy header - code - text strings - bitmap graphics - audio sample - more strings and code ) The disassembly is beginning to get useful. Hidden strings are showing up: ROM:000148F4 move.b #$30,$7FE(a5) ; '0' ROM:000148FA move.b #$30,$7FF(a5) ; '0' ROM:00014900 move.b #$30,$800(a5) ; '0' ROM:00014906 move.b #$4F,$801(a5) ; 'O' ROM:0001490C move.b #$53,$802(a5) ; 'S' ROM:00014912 clr.b $803(a5) ROM:00014916 move.w #4,(a2) ROM:0001491A move.l a2,-(sp) ROM:0001491C jsr (a1) Still no luck getting anything else than audio disc to work though. I'll keep digging ;-) CF
No prob Assuming how mad is a disc access from a so low level... I wonder how you'll figure out the directory reading process from assembly Good luck man I think the disc format is not iso 9960 compatible and may just have a sort of file table at start of the disc which point to the files (file table may include "sector", "lenght", "type" and "name"...). That's just an idea... it can be of course a 9960 compatible table too
Finding a CD for it is your only hope My guess is that it's ISO9660 compatible but needs specific filenames and perhaps a Gamars header as opposed to just an index file. There's also the VERY slight possibility it works similarly to the "Game VCD"s of MD VCD/DVD players where a special disk is required but I don't think so. I say this because Gamars did make the VCD players for Playstation shortly after this product. Also are you sure your RAM identification is correct? Two 4-bit wide RAMs makes 8-bit, MD games are strictly 16-bit. I don't think the unit preforms two DRAM reads for every 68K access, DRAM overhead is too much.
You're probably right, but I won't give up yet ;-) The plan is still to find that out from the deadlisting I have made of the BIOS dump I think I have located some string parsing functions and CDROM functions... Thanks! That is worth checking out I have a Gamars VCD card in my PSone.... Good point! Strange. I will check again after I get some sleep. Have been documenting the disassembly for hours.... Thanks again for your help Calpis!!! CF
