>
> This might be a second post, I got a weird error message the first time.
>
>
> I just scanned my technical manual for the GNT 4604/5 which has many
references to the 4601.
>
> It does include schematics. You can find it here:
>
> http://www.dvq.com/docs/GNT/
>
> Bob
>
Many, many, many thanks! I bought a new-old-stock GNT-4604 about a decade
ago. It was so exciting to open the foil seal and --- nothing worked. I
did find the problem. It had cold solder joints on the control board. But
having the service manual means I can keep it running for years to come.
I also have a GNT-4601 so I'm doubly appreciative. Your work will not have
been in vain!
Amardeep
Date: Sat, 21 Jul 2012 21:31:20 +0100 (BST)
From: ard at p850ug1.demon.co.uk (Tony Duell)
To: cctalk at classiccmp.org
Subject: USB to GPIB interface
Message-ID: <m1SsgKj-000J4gC at p850ug1>
Content-Type: text/plain
It's of no real interet to me at the momnet (obivously) but this
month's
Elektor magazine (the summer double issue, so it's not cheap!) has a
project to make a USB to GPIB interface. It's little more than a
programemd PIC which directly drives the GPIB lines without buffers. I
don't like that much, but...
I think you can get source code for the firmware (apart from the USB
routines, which are standard routins from Microchip).
I have successfully controlled some GPIB gear with just a parallel
port, not even a pullup resistor needed.
Jon
With reference to my reply to Chuck's message, I've now dug out the
schematics.
The Sirius printer interface uses a 6522 VIA (at location U15L o nthe
mainboard). Port A is bufferec by a 75160 and fet ot the data pins on the
'Centronics' connector. Port B is used for the handshake lines, in
ascending bit order : DAV, EOI, REN, ATN, IFC, SRQ, NRFD, NDAC. Tese are
bufferec by a 75161, always in controller mode (DC is grounds). NRFD and
NDAC (o nthe 'host' side of the buffer) also go to CA1 and CA2
(respsecviely) of the VIA
The 'Talk' (buffer direction) line is controlled by PB0 of the 'system
VIA' at loccation U12L
The pinout of the 'Centroics' socket is :
DAV 1 19 Gnd
D0 2 20 Gnd
D1 3 21 Gnd
D2 4 22 Gnd
D3 5 23 Gnd
D4 6 24 Gnd
D5 7 25 Gnd
D6 8 26 Gnd
D7 9 27 Gnd
NRFD 10 28 Gnd
SRQ 11 29 Gnd
N/C 12 30 N/C
NDAC 13 31 N/C
J 14 32 NDAC
EOI 15 33 Gnd
Gnd 16 34 REN
FG 17 35 ATN
NC 18 36 IFC
A couple of non-obvious ones : 'J' (pin 14' is connected to ground via
the jumper E26-E27 (which is not normally fitted I think). FG is frame
ground (mains earth), not logic ground.
I/O chips i nthe Sirius seem ot be memory mammed for some odd reason. I
think the addresses are :
GPIB VIA : 1110 1xxx xxx0 001x rrrr
System VIA : 1110 1xxx xxx0 010x rrrr
where rrrr is selexts the VIA register in the obvious order.
-tony
Hi everyone,
I'm getting ready to see if I can get all those PDP-11's running
properly. I have most of the test equipment I'm likely to meet -
multimeter, oscilloscope, current tracer, logic analyzer - but figured
that extender cards for Qbus and Unibus might come in very handy. Does
anyone have any they'd be willing to part with?
Camiel.
I spotted a listing for the TNIX user manuals and a set of floppies in Tucker's manual
list, so there is a standalone disk and a dump of the file system with the native tools
package on bitsavers now, along with the manuals.
The standalone formatter seems to be really fussy about what kind of disk it will format.
I tried a Seagate ST4096 and a Maxtor 1140, and couldn't get either to go even though they
had more heads and cylinders than the Micropolis 1304.
It's of no real interet to me at the momnet (obivously) but this month's
Elektor magazine (the summer double issue, so it's not cheap!) has a
project to make a USB to GPIB interface. It's little more than a
programemd PIC which directly drives the GPIB lines without buffers. I
don't like that much, but...
I think you can get source code for the firmware (apart from the USB
routines, which are standard routins from Microchip).
May be of interest to somebody here....
-tony
Just spreading the word amongst a few of the groups that may have interest and talent in older and more efficient programming past. http://minigamecompo.weebly.com/index.html has begun and will be accepting submissions I believe until November 30th (2012).
For those who aren't familiar this is a competition to write the best game they can in the category of under 1k, 2k, or 4k of code for various (usually 8-bit) platforms. They have some screen shots of previous programs that have competed to see what sort of stuff comes out of it. I always find it entertaining.
I have no affiliation with them, just helping spread the word since I haven't seen it announced in my usual hangouts yet.
- John