Anyone know anything about this unit? Top: Under: Back: PCB: PCB: PCB: 2Mbit onboard + 2Mbit on memory board CF
Looks to be usefull for the white pc engine, to add s-video & presumably stereo sound out over the headphone jack.
It almost looks like a game copier/backup unit as well... Have you tested it with a PC-Engine? I'd also recommend covering up that EPROM window with some black tape if you plan to take any more photographs
I only have a Duo-R. Looking for a Core Grafix now I dumped the EPROM Didn't see any strings... Can you recommend a disassembler? CF
it says CD-RAM system, it says Doctor, and it has 4M written on it. Sounds like a coding tool. Maybe u can use the I/O to transfer images into its RAM and execute? Like a cheap devkit?
Definitely a copier, definitely unusable without the parallel cable w/o reversing the circuit; else I would have bought it first! Since the unit has DRAM, the PLD must contain registered logic which means reverse engineering isn't a reasonable option. MAME has a free Hu6280 disassembler if you want to poke. Look through a tile editor for font patterns instead of ASCII strings, that'll be more fruitful. Edit: also it doesn't add S-video (of course, there is no RGB encoder!), maybe it's compatible with MD2 cables, probably not though since it's probably older than MD2.
That would be pretty cool Thanks for your expert advice Calpis! I can confirm that a bitmap font occupies a large part of the ROM. Going to check out the MAME disassembler, but I was hoping there was a 6280-compatible CPU that IDA supports (65C02?)... CF
if it's a backup unit, I don't understand why it's mounted at the extension port. MGD1 and MGD2 use the Hu-Card slot. Maybe it's a IFU clone?
The expansion port contains everything from the Hucard slot and more, it also makes it look less suspicious. 65C02 wouldn't be close enough to the Hu6280, there are a lot of instructions that are new and perhaps replace old opcodes (which would make the output incoherent.) IDA also isn't that great of a disassembler for non intel code IMO, better to just disassemble manually with freeware tools.
It didn't look too good, so I think you're right, hehehe ) I think it rocks for Sega 68k. Doing pretty good on that Alma CDX thing... CF
The official dev kit does all functions via the exp port. This has extemely important reverse engineering possibilities for a diy homebrew dev kit.
There is nothing to reverse engineer other than the unit itself which requires a lot of programmable logic which most people can't program anyway. Anyone wanting a "devkit" would be better off making a simpler homebrew one (see below) Because the unit has a BIOS, the interface is implemented in software with memory mapped registers for I/O to the parallel port. PCE is one of the simplest consoles to make a "devkit" for since the cards are single 8bit ROMs and require no decoding logic. To make an in system programmable "EPROM-emulator" for PCE, you'd need a whopping $10 of off the shelf parts. Rundown: -SRAM (most expensive) -address line counters -tristates to isolate system/counter -latches to control programming/isolation (-if you want to get fancy, a MUX to "fix" address lines or this can be simulated in software.) (-battery circuit (resistors, transistors, diodes, battery) could make it nonvolatile and hot swappable)
PCEDis is an Okay PCE disassembler. I can't find the link to it, but I believe it was written by Dave Shadoff. (Or if you send the ROM dump to me, I can take a look at it...)
