Home Page Forums MAME MAME Requirements?

... and here's some more. This is a scan of the "PC 100 System Specification" ... and is very informative about the way the various parts of the system talk to each other (e.g. shared RAM, what CPU gets to control which pieces of hardware).

PC100 System Specifications

Robert

Greetings fellow computer preservationists!
'rfka01' got me interested in this and I am attempting to come up to speed on the rainbow project. I've done some minor simulation work of PDP11 systems in the past and am amazed at the scope of MESS. It will be a while before I can make any useful contributions, but I will watch with interest.

I haphazardly maintain
http://www.willsworks.net/pdp11/decmicro.htm.
So I am a Rainbow fan. I would also like to submit DEC's VT-180 (aka Robin) computer for consideration. It is described on the page above with links to the Technical Reference Manual and some disk images which are available at
http://bitsavers.org/pdf/dec/terminal/vt180/
This was a Z80 based CPM 2.2 system with 64Kb of memory which was housed in a VT-100 terminal. I think its similar to the Z80 half (CPM80) of a Rainbow.

I've also located some ROM images at
http://www.dunnington.u-net.com/public/DECROMs/
per the file, ROMlist, I believe 23-017E3 and 23-021E3 to be the boot ROMs. The character display was handled by the VT-100 board, and I suspect that 23-018E2 will work as a character generator, but a quick inspection shows it also includes some of the setup strings.

I own a couple of both these systems, although only the rainbow is physically accessible at the moment.

Will

This is the keyboard ROM for the Siemens PC-D complete with two pictures of the pcb inside.

Siemens PC-D keyboard ROM and pix

The DMV has D8741AD inside the keyboard which I can't read yet, I haven't found a way to get inside the Rainbow keyboard without destroying it, maybe Will can shed a light onto what to expect there.

Robert

I'm not as prolific, nor dedicated as my internet friend rfka01!
However I did just log in and see he pointed his finger at me last month regarding Rainbow Keyboards. I have never opened one up, but do have some spares I will be near next month if that is required. However I think emulation would be the way to go and the link below gives a lot of information:
http://www.netbsd.org/docs/Hardware/Machines/DEC/lk201.html

In overview the LK-201 keyboard used RS-232 at 4800 baud. I
believe his interface was used with most of the Decmates, the Pro-350, and some of the Microvax which is why its on the netbsd site. On the Rainbow, Decmate, and Pro-350 the 4 pin LK-201 connector plugged into the back of the VR-201 monitor and was then routed to the DB-15 monitor connection on the back of the Rainbow. The Update site below has a lot of good old rainbow info, the file indicated below gives pinout info for this DB-15.
ftp://ftp.update.uu.se/pub/rainbow/doc/VR241.txt

So in terms of hardware, I believe the keyboard acts like a serial line unit on the appropriate pins off this DB-15. On the Microvax the keyboard plugged directly into the CPU unit. Its off topic, but for the record I have a microvax that I occasionally play with using my PC as a serial terminal for the keyboard.

I have always used the MSDOS bios interface to interact with the Rainbow keyboard when writing code for it, and am not sure where that fits in. Presumably the keyboard Uart interacts with the bios routines but I have no knowledge of this level. If useful I can document the key codes produced by the bios routines on my rainbows, let me know.
But I fear we need to obtain listings or disassemble the bios a little to see how it interacts with the keyboard to do an emulation.

I'm interested in this entire project, but primarily in the Graphics option card with which I have been experimenting. I have a copy of a manual similar to the one rfka01 made available a few weeks ago in postscript format, but had never seen the *.DOC version (although they seem identical). For those interested in documentation, if you haven't seen it there is an on-line version of the NEC-7220 manual available, although most of this information is duplicated in the link rfka01 posted, the additional DEC ports and differences regarding the Rainbow are of significant interest, as are the graphics pixels apparently available in the bitmap which can't be displayed!
http://electrickery.xs4all.nl/comp/qx10/doc/nec7220.pdf

luck!

oh dear f***ing god. an LK201 keyboard is the most evil unmaintainable piece of equipment DEC ever put out; It was followed by the mostly-backwards-compatible and more tolerable LK401 keyboard (which doesn't fail QUITE as often and is not QUITE as irrepairable from what I've been told). It has an unusual propensity for spontaneous failure, and the entire inside is held together with melted plastic spikes, making it impossible to disassemble and repair. The membrane (it is one of the earliest 'open membrane' (read: cheap) keyboards made is held permanently bent (unlike the membrane in an ibm/lexmark model M keyboard, which despite being clicky does use a membrane, but one held perfectly flat), causing it to wear out unusually quickly from constant stress on the plastic; also holding keys down for an extended period of time by something sitting on top of the keyboard will cause the membrane layers to weld themselves together causing stuck keys, which because of the plastic spikes is impossible to fix. Not to mention that the keyboard mcu will fail its power on self test and refuse to work if any keys are stuck down, rendering the keyboard an obscene giant paperweight.
to make matters even MORE fun: the way the membrane is attached to the pcb with the MCU on it is using these metal one-piece clamps, which make it almost completely impossible to remove the membrane without damaging it further (you have to sort of shove part of a credit card in between the membrane and the contact spikes, them yank the membrane out hopefully not scraping off the contact layer on the credit card!)

There are two versions of the LK201: one has red LEDs and has an Intel MCS-48 series MCU, and the other has green LEDs and has a mc6800-series (or maybe Hitachi 6300-series) MCU; the clock crystals used on both versions are different.

I have a damaged/irrepairable LK201 of some variety here, as well as two working ones, one with red LEDs, and one with green LEDs.

No offense is intended to rainbow_will by this post, I just can't stand the rampant reliability issues with lk201 keyboards; fortunately there seem to be quite a lot of them out there so getting spares is not a major deal yet.

The lk201/401 is used by, at least:
VT220
VT240
VT320
VT340
Rainbow
VT420
VT440?
The vt520 does not use it; it uses a plain ps/2 keyboard.
Although a special VT520 PS/2 keyboard with extra DEC keys is what you're supposed to use with it, it will work fine with any PS/2 keyboard.

LN

no offense take Lord Nightmare, but interesting comments. I really don't think I've had one fail, but given your input I don't think I'm eager to take one apart either!

I found (long ago) one other source which is a zipped collection:
ftp://ftp.update.uu.se/pub/rainbow/doc/rbtecdoc.zip
I recommend miscin.doc which has some discussion of where
the keyboard buffer and counter are stored in memory.
And rbgibm.doc which talks about differences between ibm
and rainbow bios.

I still have not attempted to look at the code in detail, but how do you know where to locate the ROM images you guys obtain?

Regards, Will

Reading all this with interest ... thanks for all the information rainbow_will and LN ... let me know when to chime in and trawl for specific information.

Robert

Sorry, I would like to retract yesterdays question about where to place the ROM images in memory, the Rainbow 100 Technical Manual, pc100tm1.pdf, has more info on this than I can
absorb! It also contains a good description of how the keyboard 8251A PUSART works, see section 4.4.14 starting on pp 4-75

Some more technical documentation about the DEC Rainbow 100

Rainbow 100 Technical Docs

There's some interesting stuff about the interplay of the processors, also a good description of the video part.

Robert

I've put system disks of the PCs in question here through the Anadisk floppy format analyser, these are screenshots from the program.

NCR DMV:
DOS disk:




CP/M-80:


CP/M-86:


CP/M-68k:
http://dl.dropbox.com/u/55419307/DMV%20CPM-68k.JPG