Date : Sat, 11 Nov 1989 22:16:04 GMT
From : firstname.lastname@example.org (Rob Tillotson)
Subject: NEC PC-8500 info wanted...
Hi. I have a NEC PC-8500 computer, and I am looking for any sort of
information on its internals that you might have. The only information
I was able to get from NEC was the service manual for the computer itself;
unfortunately, there was no information on peripherals or anything even
closely related to programming. So, I am searching for any sort of
documentation other than the NEC service manual that is out there.
My system consists of the basic PC-8500, plus a PC-8508 128k RAM module
(with a couple of ROM sockets I would like to fill), a PC-8431 monitor/disk
interface, and a PC-8441 disk drive. If you have any information at all
about any of this stuff, please send me some mail. I am particularly
1. information on the extended BIOS routines. I have had some
success at disassembling the BIOS but there are about 100 routines
and I have so far only figured out what about 1/3 to 1/2 of them
2. I/O port assignments. So far I know the ones for the disk drive
and video interface (from the documentation) and partial information
on the parallel port and memory mapping register, but there is much
more that I haven't been able to figure out from reading the ROM.
The schematic is no help either since all of the chip selecting and
such is done by a couple of custom PALs.
3. how to set up a ROM so it will show up in the application menu
4. pinouts for the disk drive, both the internal connectors (so I can
add another drive) and the interface connector (so I can turn my
Amiga into a disk server... the manual describes the protocol in
detail but they forgot to give the pinouts of the cable)
5. Leads on where I can find any application ROMs that might have ever
been produced for this thing.
For those who might be unfamiliar with this machine, it is a nice little
laptop with a good keyboard, flip-up 80x25 LCD, Z-80 compatible CPU, 64k RAM,
300 bps modem, and applications in ROM (CP/M 2.2 with a menu driven CCP,
WordStar, SuperCalc, telecommunications, and simple database)... sort of like
a Tandy 100 on steroids.
As I said, *any* information you can send me will be appreciated. Likewise,
if you are interested in the (quite incomplete) information I have dug up
in disassembling the 8500's BIOS, let me know. Thanks...
Rob Tillotson Internet: email@example.com
320 Brown St. #406 BITNET: ROBT@PURCCVM
West Lafayette, IN 47906 Fido: 1:201/40.302