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NEC APC-III #47027 12/24/08 10:39 AM
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MustardMan Offline OP
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Greetings all.

This is my first post on this forum, and I am having difficulty with attaching files. After reading the FAQ, either I have to make a few more posts before I can attach, the FAQ is out of date, or Firefox is not playing the game. I get no "File Manager" icon.

Anyway, I have an interest in the NEC APC-III computer, and I have a couple stored in the garage. I have dumped the ROMs, and would like to submit them to the project. I noticed that this is one of the systems that MESS is after (both ROMs and other info).

My first real PC was one of these machines, and I have some software that will only run on them. The APC-III was a contender in the IBM-PC race (and NEC lost). As such, the APC ran MS-DOS, and all programs that used DOS calls only would work fine on both systems. However, because the APC was a different arhitecture, software that called BIOS or wrote hardware direct would not work.
Apart from actually having a couple of machines, I also have the System Reference Guide (a lot of hardware info, including ports & device register detail) and the Maintainence Guide (primarily circuit diagrams).

Once being a hardware engineer, I have no problem following this stuff, but am not really up to speed on software. I think I can contribute to creating a "config" file, but have little clue about where to start.

First step is to get the ROMs up there. The manuals are all paper, and I am trying to find someone with an auto document feeder so I can scan them in less than a day!

Any help appreciated.

MM.

Re: NEC APC-III [Re: MustardMan] #47029 12/24/08 02:52 PM
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Lord Nightmare Online Content
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Sending instructions via PM...

LN


"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"
Re: NEC APC-III [Re: Lord Nightmare] #47038 12/25/08 10:29 AM
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MustardMan Offline OP
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Thanks for the instructions - ROMs dispatched.

I had a read of the sample Driver Skeleton on the wiki, but didn't get much out of it - over my head sorry frown

I don't know if it is supported in MESS (probably is), the APC-III used commands to instruct the graphics chip rather than memory mapping like the older computers did (TRS-80 etc). Of course, all modern PCs do this now, but I assume customised routines would have to be written to allow MESS to emulate this behaviour?

Cheers,
MM.

Re: NEC APC-III [Re: MustardMan] #47039 12/25/08 01:26 PM
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Bletch Offline
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MustardMan, do you have any information like a memory map and what chips the APC-III used? MAME/MESS already contains many implementations of CPUs, video chips, interface adapters and other hardware, and it would be interesting to know how much the APC-III had that we already have.

Re: NEC APC-III [Re: Bletch] #47052 12/27/08 09:02 AM
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MustardMan Offline OP
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The APC-III used two graphics controller chips, one for text & the other for graphics. Either controller could be selected, both were the uPD7220.

I am awaiting access to an ADF scanner so I can scan the two technical manuals I have (probably 200 pages or so). A lot of info in those.

However, in a nutshell, one controller had two pages of text, the other one(two?) page of graphics. Double if the resolution of text/graphics was diminished. Either controller could be selected, or a mix of both could be done, the text characters taking precedence over the graphics. The text was CPU access only (ie: memory mapped) with no GDC access (Graphics Display Controller). The graphics was accessable by GDC commands or memory mapped CPU.

VRAM for the text... (80x25 or 40x20)
A0000h = Page 1 of characters
A1000h = Page 2 of characters
A2000h = Page 1 of attributes (flash, underline, etc)
A3000h = Page 2 of attributes

VRAM for the graphics... CPU access... (640x400 or 640x200)
A8000h = Colour A
B0000h = Colour B
B8000h = Colour C

In the cheap version, only monochrome was supported, being colour A.
In the colour versions, I *think* A=green, B=red, C=blue.

Graphics VRAM could also be accessed by the GDC, but had different logical addresses (4000h, 8000h, C000h respectively). Also the LSB/MSB of bytes was reversed (why?!).

Hope this little bit helps, although the full technical manual info would probably help a lot more! I'm working on it!!

Cheers,
MM.

Re: NEC APC-III [Re: MustardMan] #47167 01/03/09 04:08 PM
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I'm pretty sure this was the in-house PC I used for dumping when I worked at Filtek Australia back around 2001. IIRC, it was scrapped a few years ago but at that time I pulled it apart and I'm sure I remember an 8751 MCU. Probably the keyboard controller. If one of them can be sacrificed, the chip could be submitted for decapping. Maybe there's other chips on the mainboard that are decapping candidates too.




Guru

Re: NEC APC-III [Re: MustardMan] #113693 07/24/18 08:14 AM
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Alegend45 Offline
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For some reason, necdemo in the APC softlist is marked as unsupported, but when I tried it, there was nothing obviously wrong with it. So are there any reasons I don't know about or?

Re: NEC APC-III [Re: MustardMan] #113694 07/24/18 11:54 AM
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Reuental Offline
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Is the APC III compatible to some extent with early PC-98 software? I've seen an ad where the PC-98 pinball game Moonball was running on it, it might have come with the machine.

Re: NEC APC-III [Re: MustardMan] #113696 07/24/18 03:12 PM
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Semi-offtopic:
The original NEC APC (which I think may have been called something else in japan?) has an undumped upd1771 used as its sound generator chip. We don't have a CPU core for the upd1771 yet (it is entirely undocumented other than vague info from patents, and we need to figure the opcodes out from the decoder PLA on the decap, which will be an adventure itself), but kevtris and plgdavid figured out how to dump the ROM part, which is easy with a cheap 16-line usb logic analyzer.

LN


"When life gives you zombies... *CHA-CHIK!* ...you make zombie-ade!"
Re: NEC APC-III [Re: MustardMan] #113697 07/24/18 08:30 PM
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I don't think the APC line were sold under a different name in Japan. They were designed for export markets, particularly the US, and aimed at businesses. The graphics capabilities were supposed to be the big selling point.


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