Cable or Pinout for NEC PC-8001mkII

HxC Floppy emulator support for all others computers...
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cjs
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Joined: Sun Sep 08, 2019 8:34 am

Cable or Pinout for NEC PC-8001mkII

Post by cjs » Sun Sep 08, 2019 9:46 am

I have a NEC PC-8001mkII computer (sometimes incorrectly called a "PC-8001mk2") which has a built-in disk controller for PC-8000-series double-density 5.25" drives. (The English and Japanese Wikipedia pages contain a bit of information about this model.)

The floppy disk connector on the back is a female 36-pin micro-ribbon connector, also known as a "Centronics" connector, similar to printer and SCSI drive connectors from the 1980s. That Wikipedia link shows the male and female connectors, and a picture of the female connector on the computer is attached to this post.

Unfortunately, I have so far been unable to find a pinout for that connector. Given the number of pins, I'm guessing that it's moderately likely that they're directly running Shugart's 34-pin SA-400 interface through that connector. I have an oscilloscope; if you have suggestions for me about how to reverse-engineer the interface I'll happily take them.

I'd like to use an HxC Floppy Emulator with this machine, both for N-BASIC and to run CP/M. So I have the following questions:
  1. Does anybody know what the pinout would be for the 36-pin micro-ribbon connector, or know anybody who makes/sells cables for it? (I'd prefer to make my own cable, as I have the parts for this, but I can buy one to reverse-engineer the pinout if that's absolutely necessary.)
  2. Has anybody already used an HxC with this or any other PC-8001-series machine?
  3. Is the disk format the same as the PC-8801 and/or PC-6601, both of which are on the HxC supported computers list? (The PC-8801 was the 16-bit series that followed on from the PC-8001 series, and the PC-6601 series was similar to the PC-8001 series but cheaper and with arguably better graphics.)
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NEC_PC-8001mkII_floppy-disk-interface.jpg
NEC_PC-8001mkII_floppy-disk-interface.jpg (76.51 KiB) Viewed 202 times

Jeff
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Re: Cable or Pinout for NEC PC-8001mkII

Post by Jeff » Tue Sep 10, 2019 7:41 am

Have you the external floppy unit ? If so you can find the pinout from the internal floppy drive pinout which is probably standard ?

cjs
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Re: Cable or Pinout for NEC PC-8001mkII

Post by cjs » Tue Sep 10, 2019 4:17 pm

Jeff wrote:
Tue Sep 10, 2019 7:41 am
Have you the external floppy unit?
No, sadly, I do not.

Jeff
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Re: Cable or Pinout for NEC PC-8001mkII

Post by Jeff » Wed Sep 11, 2019 10:24 pm

cjs wrote:
Tue Sep 10, 2019 4:17 pm
Jeff wrote:
Tue Sep 10, 2019 7:41 am
Have you the external floppy unit?
No, sadly, I do not.
Any schematic / Service manual ?

cjs
Posts: 3
Joined: Sun Sep 08, 2019 8:34 am

Re: Cable or Pinout for NEC PC-8001mkII

Post by cjs » Sun Sep 15, 2019 6:36 am

Jeff wrote:
Wed Sep 11, 2019 10:24 pm
Any schematic / Service manual ?
I have been unable to find one. If anybody comes across one (in English or Japanese), I'd love to have a copy.

It's looking as if I'll have to sit down with a 'scope and work it out for myself.

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