Saturday, January 23, 2016

Pioneer UC-V102 - Part 4

Besides the quantity of expansion slots, Pioneer UC-V102 isn't so different than other MSX2. It's not so uncommon to japanese MSX2 machines with a more "professional" look (translation: separated keyboard) to have special features like genlock, rs232-c or both. No "turbo" mode, no memory beyond the 64KB (minimal for MSX2), etc.

The expansion slots

CPU: Z80 @ 3.58MHz
VDP: Yamaha V9938 with 128KB VRAM
PPI: MSX-System II
Sound: PSG equivalent inside MSX-System II
Storage: Floppy Disk Interface with two 3.5in 720Kb Floppy Disk Drives
Keyboard: separated keyboard compatible with the Mitsubishi ML-G30 one
Additional features:  RS232-C, Superimposer (3 inputs)

The MSX-ROMs are four ICs, behind a metal bar (the one that holds the floppy disk drives and the expansion slots). They are identified in the silk as MM, ME, RS and DS: MSX Main, MSX Extended, RS-232C and Disk-ROM.

Panoramic view from inside the Pioneer UC-V102.
The ROMs, V9938, VRAMs, FDC are all behind the
floppy disk drives and this big metal bar that
hold them. Is a bit hard to reach them.

There you can see the Pioneer PD5044, the MSX-System II,
the RS-232C circuitry, the Z80.
All the ICs are identified by its names in the mainboard, that helps a lot. It's much easier to remove the bottom metal plate from UC-V102's cabinet than to disassemble all the machine only to free the motherboard and see the the PCB from up.

The mainboard from below.
You can see that all ICs are identified in the board prints.

This is the part with a most unobstructed view, that we can see from up.

This is the part behind metal bars and floppy disk drives.
The four ROMs that are mapped on MSX slots are at right.
Without the RAM and ROM chips, the main ICs in Pioneer UC-V102 mainboard are:

Mitsubishi M5L8251: UART compatible with i8251
Mitsubishi M5L8253: PIT compatible with i8253
Mitsubishi M5W1793: Floppy Disk Controller, compatible with WD1793
Pioneer PD5044: Custom chip, the only identification that I found was "UCV102"
Sharp LH0080A: Z80 compatible
Sony V7010: Genlock
Yamaha S1985: MSX-SYSTEM II
Yamaha V9938: Video Display Processor

The Pioneer PD5044. Next to him a switch "NORMAL" and "TEST".
In "TEST" position nothing happens when the machine is turned on.

The only IC that is unusual in MSX systems is the Pioneer PD5044 but, close to it, there is something a bit more unusual, two additional ROMs:

Toshiba TC531000: 128KB ROM
Toshiba TMM23256: 32KB ROM

Where those ROMs are mapped?? I had no idea. To be fair with myself, I just noticed them while writing this post, while I was listing the ICs. Thanks to Leonard Oliveira and mars2000you, I did the dump of the 128KB ROM using KANJIROM.BAS and... it's the same Kanji-ROM of Mitsubishi ML-G30:

29f0cee1e2fb77507b6e40d8a743d99e  UCV102KJ.ROM
29f0cee1e2fb77507b6e40d8a743d99e  mlg30kfn.rom

After this discovery, I made the same test against the other ML-G30 ROMs:

60b6a10f68bfd076d35ff58797405f76  BIOS2.ROM
60b6a10f68bfd076d35ff58797405f76  mlg30ext.rom

75c8e28609c50afb67f64c46a60cf7d2  BIOS.ROM
75c8e28609c50afb67f64c46a60cf7d2  mlg30bios.rom

Mitsubishi's keyboard, Mitsubishi's BIOS, Mitsubishi's SUBROM (this one is shared by more manufacturers, probably it comes from a common source, ASCII is a good guess), Mitsubishi's Disk-ROM, Mitsubishi's Kanji-ROM, machine built with Mitsubishi's clones of many ICs, etc. And the questions from the last post that we thought could go unanswered forever now has an answer: very probably Mitsubishi did the UC-V102 for Pioneer.

Like Sanyo built many MSX machines for Philips, looks that this time Mitsubishi built this machine for Pioneer. Even the Pioneer PD5044 could be designed by Pioneer and made in silicon in a Mitsubishi foundry.

Well, Pioneer UC-V102 is still the only MSX2 from Pioneer...

...but built by Mitsubishi.

No comments:

Post a Comment