VTxx Dumping Thread

[davidstech]

NewRisingSun2

Feb 2 2018, 06:35:14 PM

Well, I'm going to call it a day. Here is my progress so far. Use mapper 270 for FC Pocket 638-in-1 (and the two split ROMs), mapper 296 for DGUN-2573 and FC Pocket 472-in-1 (has the extra 128 game cartridge been posted?). I have not made any progress on 246 in 1 MOGIS M320 (VTxx) unfortunately.[/quote]Awesome thanks for your work! The 128 in 1 cartridge ROM is not separate, nor can it easily be split. The ROM is combined and checks for the value of the IO port $412d on startup. If it equals 0x06 the 128 in 1 cartridge menu is shown, otherwise the 472 in 1 menu is shown. I use a dip switch to implement this in MAME.

[NewRisingSun]

Successfully implemented the DIP switch. By the way, the split ROMs of Family Pocket don't fully work, as a few games (57/58 in 508-in-1) are taken from the other half of the ROM.I would say that DGUN-2573 is badly dumped? The 16 KiB CHR-ROM bank for the thumbnail picture is stored in $1D, then by the VBlank handler written to $2015. Banks $00-$3F are striped, banks $40+ look normal. The outer CHR-ROM banks are   zero. The first $20000 bytes in the file are just 00 00 FF FF, producing the striped pattern instead of the expected thumbnail.

[davidstech]

Quite possible, it's not my dump so there's nothing I can do. I have ordered one on Amazon Prime to have a look at tomorrow though.

[NewRisingSun]

I've spent time trying to deduce how DGUN-2573 selects between the original VT03 palette, with the 4-4-4 bits meaning hue/luma/saturation, and the new palette with the 4-4-4 bits meaning R-G-B. No CGRAM bit, no $2xxx and no $4xxx bit seems to tell this. The only method that reliably tells them apart on all 220 games correctly is whether the game attempts to adjust for the original VT03's hardware bug when using DMA transfers to CGRAM (by writing an address of $3F01 even though the data will go to $3F00 because of the aforementioned hardware bug). On the VT03, that of course only works in NTSC mode, so $4119 bits 3 and 4 must return 0 for this to work, and the emulator must of course replicate that hardware bug.

It still seems like a dirty heuristic, but given that the PCM sound code seems to read from $4014 to tell apart NTSC from PAL, instead of reading from $4119, to adjust either frequency or sample length, that might just be what the actual hardware is like. The only way to tell for sure is to find a way to run a test ROM on the hardware.

[davidstech]

For some reason I'm not seeing CGRAM DMA at all in most of the games in MAME. I'm curious, what is $4014 returning when read?

[NewRisingSun]

I don't what it is actually returning, but the game checks for bit values $01 and $02. If $02 is set, a different PCM sound parameter value is used.

CGRAM DMA will be used at least by Champion Boat (#7) and King (#220), and by the menu.Actually, $4014 seems to be related to the PCM sound channels. I also just noticed that the sound effect and the music are supposed to play simultaneously. In other words, there are at least two additional PCM channels. This complicates matters a bit.

[davidstech]

I've started looking at the DGUN-2561 to see whether there is any hope of emulating it. I'm starting to think it's some kind of more enhanced part i.e. the VT368 or VT369. It seems to be making accesses to addresses in VRAM that wouldn't make sense for a simpler VTxx part (e.g. $3c00-$3eff). It also looks like it might have a VT168-style ALU at 0x413x (it's at 0x213x on the VT168), but I'm not sure about that. I also see a few reads and rights to various addresses $484x, $488x and $4ffx, not sure what they would be a peripheral or whether it's just RAM at $4800 .. $4fff,

[NewRisingSun]

246 in 1 MOGIS M320 (VTxx) also writes to VRAM $3C00.

[davidstech]

I think this is starting to make sense. The SY-88x, M320, the DGUN-2561 and the Lexibook Cyber Arcade are probably all the same chipset, which I imagine is something like the VT368/VT369. That would explain the SY-88x using VT168-style RGB555 colour palette data, as it's some hybrid between the VT168 and the VT32/older NES-based parts, which unlike the VT168 also has backwards compatibility.

I notice MOGIS sell a console, the M200, which has enhanced games that look much more like VT168 (there's a video of it on Taobao here as well as NES games. This is probably also the same chipset, I have ordered one to dump.

If MOGIS are associated with Wellminds, who have various similar systems on their website, their list of platforms are "VT02、VT03、VT168、VT32、VT368、VT369、SPG220、SPG243、SPG288、GPL16218、GPL16258、ST2302、EM78P153". Obviously this is something VT, whilst it could be the VT32 I think the VT368 or VT369 is most likely.They also mention WS109 series encryption ICs. One of the games lists for the M200 had "WS107" in the name of one of the games, which does make me fear these new consoles have some kind of authentication/encryption chip which will make emulation harder (but probably not impossible with some creativity...)

[kelvin donna]

NewRisingSun2

Feb 3 2018, 01:44:44 PM

246 in 1 MOGIS M320 (VTxx) also writes to VRAM $3C00.[/quote]dear newrisingsun2, can you fix the football rom please

NewRisingSun2

Feb 3 2018, 01:44:44 PM

246 in 1 MOGIS M320 (VTxx) also writes to VRAM $3C00.[/quote]dear newrisingsun2, can you fix the football rom please

Attachments:

• _BAD_ROM__Foot_Ball__Super_Pro_Football_hack___Unl_.nes (64.02 KB)

[Y2K05]

kelvin, forgotusername warned you that the Football game was a bad rom, and you still insisted that you wanted it.

[kelvin donna]

Y2K05

Feb 3 2018, 02:06:25 PM

kelvin, forgotusername warned you that the Football game was a bad rom, and you still insisted that you wanted it.[/quote]ok, sorry, the title screen and the football player sprites work  

also, i changed the mapper from 4 to 256 and the graphics are normal

[NewRisingSun]

Yes, changing to mapper 256 makes it run in Nintendulator-NRS, but not in anything else. I'll take a look at multicart extracts tomorrow.

[davidstech]

I am working on putting a pack of these dumps together for the latest version of NRS-Nintendulator. However, I can't get either FC Pocket or the DGUN-2573 ROMs working. The FC Pocket loads the title screen and Chinese menu fine, but the English menu gives only a blue screen. The DGUN-2573 just gives a dark green screen. I am using mapper 296, submapper 0, is there anything else I should have in the ROM header?

[NewRisingSun]

I'm not sure WHICH build I posted last. What I do know is that you need to set PRG-RAM to 8 KiB in the header, because the ROMs in fact do expect 8 KiB of PRG-RAM at $6000-$7FFF. If that doesn't make it work for you, I'll quickly post a current build, after I finish my currount round of multicart extracts (which requires me to work from a different build).