akl@mentor.cc.purdue.edu (Rob Tillotson) (11/12/89)
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 interested in: 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 do. 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... G'day, eh? --TS -- Rob Tillotson Internet: akl@mace.cc.purdue.edu 320 Brown St. #406 BITNET: ROBT@PURCCVM West Lafayette, IN 47906 Fido: 1:201/40.302