SpritesMind.Net

hey,
i just dumped the internal rom of the D-CAT16 handheld (https://www.youtube.com/watch?v=pZtLmtIrsyI)

while i'm pretty sure the dump is complete and good, no emulator runs it...you only get a black screen.

So maybe someone here is interested in looking at it:
https://www.sendspace.com/file/xjxgcr

while i'm pretty sure the dump is complete and good, no emulator runs it...you only get a black screen.

Firecore models all use an "enhanced" Genesis hardware clone (DMC RK2 chip as specified in the 8MB byte-swapped ROM dump), which, from what I remember, adds extended work RAM / CRAM / VRAM + extended VDP features/registers so the boot menu and Firecore-specific games that are embedded in that dump won't run on a real MD (or any MD emulators).

Enhanced Genesis hardware... interesting, I wonder if we can find the specifications somewhere of that extended Genesis ?

I once analyzed the Firecore Menu (it had already been dumped some years ago with a few Firecore "exclusive" games and posted somewhere btw) and from my notes it has:

- 2MB (maybe 3MB) additional RAM mapped between $B00000 and $DFFFFF (the RAM chip external to the two other globtop chips)

- 96 KB VRAM instead of usual 64KB

- 2KB CRAM (1024x16 colors ?) instead of usual 64x9-bits color palette

- an additional VDP register which function is unknown (register #24)

- some unknown hardware mapped to $A101xx (PCM sound ? Flash ROM banking ?)

I didn't dig much more into this and was only able to get games to run with (somehow distorded) FM music and black (or weirdly colored) screen

Thanks Eke for the information Extended CRAM is definitely a good idea for the megadrive... I wonder how they managed 96 KB of VRAM, did they used the initial 128K VRAM mapping ? I wonder why they added some much RAM but well, it costs almost nothing now so why not...

Stef wrote:I wonder why they added some much RAM but well, it costs almost nothing now so why not...

if its similar to Sega Gopher handheld - game ROMs loaded into it's SDRAM (IC in right bottom PCB corner I'd guess) , which is quite big and likely used/mapped as both 'cartridge ROM' and main M68K RAM (and possible for VRAM, CRAM as well)

But couldn't they just have made ROM area writeable in that case? (also wtf that RAM is actually a discrete chip? that's counterintuitive to making it cheap)

Eke wrote: - 96 KB VRAM instead of usual 64KB

I had noticed this long ago, no idea why it isn't 128KB though (or if it is and the init code doesn't bother clearing the last 32KB). For the record, the way to access the upper portion of VRAM is exactly the same as the original hardware in 128KB mode (but I guess that wasn't rocket science, just slap an extra bit - there's always room for one after all). Never found out if registers $06 and $0E were accessed though (nor it was known at the time either).

Eke wrote: - an additional VDP register which function is unknown (register #24)

Any chance there's an extra layer somewhere?

Eke wrote:I didn't dig much more into this and was only able to get games to run with (somehow distorded) FM music and black (or weirdly colored) screen

FM is already distorted on the real thing so don't expect much =P Yeah, suffers from AtGames syndrome where they use the wrong frequency and so everything is off by several semitones.

my big question is:
is everybody the same opinion as me and the dump should be correct and good...so i can assemble the handheld back together ?

Oh you shitting me...

Anyway yeah the dumps look good and both indeed look to be Mega Drive(-ish) ROMs, though the MG6025.U1 file needs to be byte-swappeed (easy fix though, should be doable with most hex editors).

Is there any way to run your own ROMs on this thing?

Wait, it's a 12$ handheld with extended ROMs, that says it supports Gen roms on the SD card? Pretty damn cheap.

The MG6025.U1 is the true DUMP!

the extracted.bin is just an extracted part of the full dump...if you run it in any genesis emulator you can at least hear the background-music!!

So I guess the emulator that's at the heart of these Firecore systems is embedded in the SoC and not the external flash? I wonder if this thing has a JTAG interface.

TeamEurope wrote:The MG6025.U1 is the true DUMP!

the extracted.bin is just an extracted part of the full dump...if you run it in any genesis emulator you can at least hear the background-music!!

OK yeah just checked, it has multiple ROMs in it (most of them misaligned by four bytes for some reason?).

Still, that dump is definitely meant to be bootable on its own, in particular the first 512KB:

Can you post a new download link. Thanks

DEEZ wrote: ↑

Sun Dec 31, 2017 6:40 pm

Can you post a new download link. Thanks

No link to the fixed dumps yet... ~Charlie