18 Jul
2022
18 Jul
'22
10:03 a.m.
Message: 6
Date: Sun, 17 Jul 2022 19:32:47 -0500
From: Chris Zach <cz(a)alembic.crystel.com>
Subject: Re: MicroVAX CTI (DEC Professional) card
To: cctalk(a)classiccmp.org
Message-ID: <448ec9e0-a5df-7dd2-65f4-6294e6ebec82(a)alembic.crystel.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Well, auction is over, I didn't bid on it, and I hope someone here got it.
That said, the more I look at it, and the more I look at a true MVII
card the more I wonder just what was missing on this card. A true MVII
has a pair of rather large custom ASICs in the center of the board and I
can't believe the 80186 (or whatever that chip is on the top center of
the board) could emulate it all.
So it would be interesting to see what this thing was and what it did.
I bought it. I know it's long odds that I can get it to do anything,
especially without that daughter card, but, waddahell, it's an
interesting DEC PRO collectible. I reckon I'll plug it into a PRO and
see if it responds to attempted accesses. If the ROM contains PDP11 or
VAX code, I'll disassemble it and see if there are any clues there.
--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason(a)comcast.net
18 Jul
18 Jul
12:47 p.m.
New subject: MicroVAX CTI (DEC Professional) card
I bought it. I know it's long odds that I can
get it to do anything,
especially without that daughter card, but, waddahell, it's an
interesting DEC PRO collectible. I reckon I'll plug it into a PRO and
see if it responds to attempted accesses. If the ROM contains PDP11 or
VAX code, I'll disassemble it and see if there are any clues there.
Good. If you can check that square chip top center and let us know if
it's a 80186 or something. It would be interesting to see if the ROM is
Microvax code, CTI code, or that other chip's code.
C
22 Jul
22 Jul
8:49 a.m.
New subject: MicroVAX CTI (DEC Professional) card
OK, got the card. The middle sized chip on the upper edge turns out
not to be an 80186 or any other processor. It's an Intel C8207 dual port
dynamic ram controller.
The EPROM is an Intel D2764. It has "TEST ROM" written on it in
pencil. It was a bit of a disappointment - first 256 bytes contain bytes
1 to FF, then a 0, then 16 more 0's, then 4096 FF's, then 0's until the
end of the EPROM. No code to be found in there....looks like it was
just something for the card to test reading.
Next I'll load it into a PRO 380 and see if it can be read/written.
I'm not actually too optimistic it will do anything without the missing
daughtercard.
--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason(a)comcat.net
17 Aug
17 Aug
12:04 p.m.
New subject: MicroVAX CTI (DEC Professional) card
The vendor who sold me the MicroVAX CTI card found the memory
daughter card. It 's missing a few memory chips, but otherwise looks in
good shape. Can;t wait to get it, add the missing chips and do some
testing. Still a long shot to make it do anything, but it's bound to help.
12:20 p.m.
New subject: MicroVAX CTI (DEC Professional) card
Wow
Can't wait to see what this thing looks like.
On August 17, 2022 7:04:56 PM GMT, Lee Gleason via cctalk <cctalk(a)classiccmp.org>
wrote:
The vendor who sold me the MicroVAX CTI card found the memory daughter card. It 's
missing a few memory chips, but otherwise looks in good shape. Can;t wait to get it, add
the missing chips and do some testing. Still a long shot to make it do anything, but
it's bound to help.
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
9 Sep
9 Sep
2:24 p.m.
New subject: MicroVAX CTI (DEC Professional) card
Took some pictures of the MicroVAX CTI card, and another odd card I
got - an 8086 CTI smartcard. See 'em both at
https://rsx11.blogspot.com/2022/09/microvax-and-8086-smartcards-for-dec.html
--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason(a)comcast.net
2:39 p.m.
New subject: MicroVAX CTI (DEC Professional) card
On Fri, Sep 9, 2022, 3:24 PM Lee Gleason via cctalk <cctalk(a)classiccmp.org>
wrote:
Took some pictures of the MicroVAX CTI card, and another odd card I
got - an 8086 CTI smartcard. See 'em both at
https://rsx11.blogspot.com/2022/09/microvax-and-8086-smartcards-for-dec.html
The 8086 card was likely for DOS or CP/M-86 programs... It likely predates
windows and didn't seem to have graphics parts / output (though I suppose
the latter could be over the bus...)
Warner
--
Lee K. Gleason N5ZMR
Control-G Consultants
lee.gleason(a)comcast.net
4:19 p.m.
New subject: MicroVAX CTI (DEC Professional) card
On 9/9/2022 5:39 PM, Warner Losh via cctalk wrote:
On Fri, Sep 9, 2022, 3:24 PM Lee Gleason via
cctalk<cctalk(a)classiccmp.org>
wrote:
I have one of the Virtual Microsystems PC-Bridge CTI boards (the
commercial 8086 board).
One of the more interesting things about it is that it has its own video
circuitry. It's built up around an Hitachi HD46505/HD6845 CRT
controller with 16 KiByte of video RAM and a character generator ROM (a
lot like a CGA). The board has one of the "long" ZIF connectors with
the additional 30 pins which carry, among other things, the analog video
signals wired directly to the monitor port. The board superimposes its
own video onto that of the system. The PC-Bridge host software just
clears the screen and turns off the cursor. In some cases the host
software can pop up host video simultaneously with the PC-Bridge video.
I assume the PC-Bridge hardware looks for sync on the "GREEN VIDEO"
signal or, possibly, the driver software uses the host video sync
interrupts to do a kind of software PLL to lock the video sources
together. Somehow the fact that both the system and the PC-Bridge board
simultaneously drive the analog video lines works out.
Hairy stuff.
Another really interesting thing about the PC-Bridge board is that it
has DEC-labelled parts on it. I'm not talking about things like
"proprietary" bus interfaces chips. The DRAM SIMMs (used for the
board's main memory) have the digital logo and a DEC part number on them
(1418744-00). In addition the chips are labelled with the DEC convention
(Exx) and are numbered E1, E2,... starting in the lower right hand
corner, with the first chip of each column being labelled on the board,
just as on DEC boards.
This made me suspect that the PC-Bridge board was actually designed by
DEC, or maybe the design was originated by DEC, and so maybe the board
Lee got on eBay was an earlier version of the PC-Bridge.
But it's clear that isn't the case -- Lee's board has a 60-pin ZIF
connector and no apparent CRT controller chip.
I was never able to get the original Virtual Microsystems software
package for my board, but from a friend I did find a Pro hard drive
image with the PC-Bridge application software installed on it. With
that I was able to regenerate the installation diskettes.
All of this is an incredibly roundabout way of saying: I was going to
offer my reconstituted PC-Bridge installation diskettes, but I really
doubt they'll work. In fact, I really doubt the software to drive Lee's
board is easily obtainable at all, given that his board bears no real
resemblance to the PC-Bridge board which, AFAIK, was the only 8086 CTI
board commercially available.
From what I see in the photograph I'd guess that the board works much
more like the DEC "CP/M" (Z80) board. In that case there's a simple
mailbox register with interrupts wired up on both sides. When using the
CP/M board the host is mostly just a dumb serial terminal with some
side-channel floppy and file access. That's why there's no graphics at
all with the CP/M board.
--Bjoren
Took some pictures of the MicroVAX CTI card,
and another odd card I
got - an 8086 CTI smartcard. See 'em both at
https://rsx11.blogspot.com/2022/09/microvax-and-8086-smartcards-for-dec.html
The 8086 card was likely for DOS or CP/M-86 programs... It likely predates
windows and didn't seem to have graphics parts / output (though I suppose
the latter could be over the bus...)
817
days inactive
870
days old
7 comments
4 participants
participants (4)
-
Bjoren Davis -
Chris Zach -
Lee Gleason -
Warner Losh