17 Sep
2004
17 Sep
'04
2:56 p.m.
Still tinkering with that Acorn Cambridge....
Firstly some background...
As Beeb owners will know, the BBC micro had 5 header plugs on the front
edge of the main PCB, which were accessible under the machine. They were :
Floppy Disk (34 pin, standard Shugart pinout)
Printer (26 pin. This is one port of a 6522, buffered, and used to
connector a Centronics printer)
USer port (20 pin, the other port of that 6522)
1MHz Bus (34 pin. This is a system bus, 8 address lines, 8 data lines,
R/W, Phi2 clock, address decoder outputs, etc)
Tube (40 pin. Also a system bus, used for the second processors)
On the Camdbridge, the floppy and Tube ports are not brought out. There's
a floppy drive built-in, and the Tube links to the 32016 second processor
board. The other 3 connectoes are linked to connectors on the rear panel --
DB25 for the user port, DC37 for the 1MHz bus (yes it's used internally
for the SCSI controller too), 24 pin Blue Ribbon for the printer port.
Now, one of the things I need to do is make up addapters from those
connector back to header plugs so I can connect normal Beeb add-ons to
the Cambridge. At leat for the User port and 1MHz bus.
If the printer port was only ever used to link to printers, then I can
make a cable from the 24 pin Blue Ribbon to a 36 pin Blue Ribbon (to fit
a Centronics printer socket). But if someone used the printer port for
something else (say as a set of outputs to control something, since it's
buffered the data lines are output-only), I suppose I'd better make an
adapter back to a 26 pin header.
So has anyone ever heard of the Beeb printer port being used for
something other than a parallel printer?
-tony
17 Sep
17 Sep
10:50 p.m.
Tony Duell wrote:
[ ... ]
So has anyone ever heard of the Beeb printer port being
used for
something other than a parallel printer?
When I was a student we used to have BBCs driving lathes, through, I
seem to recall, the printer port.
The software used had a lathe simulator that let you check your sequence
(thus saving expensive
cutting tool costs) before performing a real run.
It is so long ago that only the letters CNC remained in the bucket -
enough, though, to find this
http://www.pilotltd.net/lathe.htm
Cheers,
Dave.
19 Sep
19 Sep
1:32 a.m.
Mornin',
On Sat, 2004-09-18 at 00:56 +0100, Tony Duell wrote:
If the printer port was only ever used to link to
printers, then I can
make a cable from the 24 pin Blue Ribbon to a 36 pin Blue Ribbon (to fit
a Centronics printer socket). But if someone used the printer port for
something else (say as a set of outputs to control something, since it's
buffered the data lines are output-only), I suppose I'd better make an
adapter back to a 26 pin header.
So has anyone ever heard of the Beeb printer port being used for
something other than a parallel printer?
The docs for the Timestep weather satellite decoder which I have in
front of me say that the unit uses the printer port. It appears to feed
the 2 or 4Hz clock output from the decoder into the printer port; the
user port is tied up handling the digital representation of the analogue
satellite signal.
Incidentally, the docs actually contain full schematics (it's not a
complicated circuit) so hopefully I'll find time to build one sometime.
I was given as Astrid satellite receiver a few weeks ago which works
with UoSAT-1 (long dead) and UoSAT-2 (still running on a 50% cycle).
Being able to display satellite images on 80's hardware would be quite
cool :-) (funny how all this turned up at once via two seperate people -
I wasn't particularly looking for satellite stuff)
The Timestep decoder also works with NOAA, METEOSAT, and FAX (WEFAX)
apparently - I have no idea which (if any) of those are still
operational, but given a suitable receiver they could also be used in
place of a UoSAT-2 signal.
cheers,
Jules
11:28 a.m.
So has anyone
ever heard of the Beeb printer port being used for
something other than a parallel printer?
The docs for the Timestep weather satellite decoder which I have in
front of me say that the unit uses the printer port. It appears to feed the 2 or 4Hz clock output from the decoder into the
printer port; the
user port is tied up handling the digital representation of the analogue
satellite signal.
Incidentally, the docs actually contain full schematics (it's not a
The Maplin Mags contains schematics for the receiver and decoder. Alas
the receiver PCB was supplied ready-build so there's no alighment info
:-(. Oh well...
I do have a 'real' weather satellite receiver system. It came from
ic.ac.uk, and the bit I really wanted (and got) were the 3 I2S image
processor/display units (really interesting graphics displays for
PDP11/VAXen), complete with schematics, etc. I didn't get the computer (a
VAX), but I did get the indoor bits of the receiver -- everything from
the 137MHz 1st IF onwards, and the first local oscillator at a couple of
GHz. I didn;t get the dish or first mizer. This part is clearly home-made
(well made, but it's a 1-off -- the RF bits are built by 'dead bugging'
on a copper-clad-board ground plane in metal screening boxes, the digital
bit is on stripboard..
I am told this machine was used to receive the weather satellite images
for the BBC weather forcasts at one point....
-tony
2:17 p.m.
New subject: Satellite stuff (Was: Re: BBC printer port (ever used for anything else?))
On Sun, 2004-09-19 at 21:28 +0100, Tony Duell wrote:
Right. The Maplin one (Published in the Maplin Magazine) used only the
user port IIRC.
I've got another one (decoder only) which looks very Maplin-ey. That one
just has a pair of SPDT switches on the front along with a meter marked
0-10, whilst at the back there's just power, and a pair of DIN sockets -
both 5 pin, although one's arranged in a 'circular' pattern and the
other's more like an 'H'. No labels on any of that.
I have no idea what this one's for - it's all CMOS logic inside, apart
So has anyone ever heard of the Beeb printer port
being used for
something other than a parallel printer?
The docs for the Timestep weather satellite decoder which I have in
front of me say that the unit uses the printer port. It appears to feed from an 084 op-amp chip. Not too complex, so I'll
trace the circuit out
one day. It's marked as being for UoSAT on the PCB, but
unless data's
clocked out serially it doesn't logically seem to be for decoding
imagery.
The Maplin Mags contains schematics for the receiver
and decoder. Alas
the receiver PCB was supplied ready-build so there's no alighment info
:-(. Oh well...
I'll have to see what's in the docs I have. There's a bit of info about
calibration in the Timestep info, plus I've got a copy of the original
doc released by Surrey uni about UoSAT which is a combination of sales-
like material and useful technical information. Luckily for me it seems
to go into some detail about how to make an aerial suited to the UoSAT
satellites (as I don't have one), plus various others over on the BBC
list have been most helpful [waves at Charles and Pete]
I do have a 'real' weather satellite receiver
system. It came from
ic.ac.uk, and the bit I really wanted (and got) were the 3 I2S image
processor/display units (really interesting graphics displays for
PDP11/VAXen), complete with schematics, etc. I didn't get the computer (a
VAX), but I did get the indoor bits of the receiver -- everything from
the 137MHz 1st IF onwards, and the first local oscillator at a couple of
GHz. I didn;t get the dish or first mizer. This part is clearly home-made
(well made, but it's a 1-off -- the RF bits are built by 'dead bugging'
on a copper-clad-board ground plane in metal screening boxes, the digital
bit is on stripboard..
I'd forgotten you had that. Do you have sufficient software to make it
do something as a complete system if a suitable VAX were found, or has
that part of it been consigned to oblivion? It'd be pretty amazing to
have that grabbing images and displaying them somewhere :-) (presumably
the satellites it was designed to work with are still operational)
cheers
Jules
--
"We've had a lot of loonies around this place, but you're the first one
who thought the sunrise was made out of stale beer. Now are you going to
pick up your flute and leave, or shall I part your hair with this
crowbar?"
7:40 p.m.
New subject: Satellite stuff (Was: Re: BBC printer port (ever used for anything
Right. The
Maplin one (Published in the Maplin Magazine) used only the
user port IIRC.
I've got another one (decoder only) which looks very Maplin-ey. That one
just has a pair of SPDT switches on the front along with a meter marked
0-10, whilst at the back there's just power, and a pair of DIN sockets - both 5 pin, although one's arranged in a
'circular' pattern and the
other's more like an 'H'. No labels on any of that.
Maplin sold PCBs (with silk-screen overlay) and printed case panels IIRC.
This could be a homebrew copy, or it might (more likely) be another
magazine project.
> I do have a 'real' weather satellite
receiver system. It came from
> ic.ac.uk, and the bit I really wanted (and got) were the 3 I2S image
[...]
I'd forgotten you had that. Do you have sufficient
software to make it
do something as a complete system if a suitable VAX were found, or has
Alas not. I got the I2S driver tape I think, but nothing more :-(
As regards 'a suitable VAX', I have Unibus interface cards for the I2S
machines (hex-height, but with the A/B connector corner cut away so
they'll fit over an M930 terminator or M920 jumper), and some 'GPIT'
interface boxes (2U rack) that connect to DL11-W or DLV11-W cards. So
just about any Unibus or Qbus VAX could be used...
-tony
20 Sep
20 Sep
1:18 p.m.
New subject: Satellite stuff (Was: Re: BBC printer port (ever used for anything
On Mon, 2004-09-20 at 05:40 +0100, Tony Duell wrote:
I will ahve to dig out the Maplin docs. IIRC that one had a 20 pin ribbon
cable which connected to a Beeb user port (or to a input port card for an
Amstrad CPC...)
Yes, I'm not quite sure what I have with this bit of kit. UoSAT offered
all sorts of telemetry though, so presumably this thing's designed to
filter out some specific data...
That's a shame. There must be a lot of big and complex systems that
would make interesting museum displays which have gone the same way due
to lack of software preservation :-(
cheers,
Jules
Right. The Maplin one (Published in the Maplin
Magazine) used only the
user port IIRC.
I've got another one (decoder only) which looks very Maplin-ey. That one
just has a pair of SPDT switches on the front along with a meter marked
0-10, whilst at the back there's just power, and a pair of DIN sockets - The DIN sockets do sound Maplin-like, but I thought
they were on the
receiver. One linked to the decoder, the other to a tape recorder (you
recorded the analogue signals from the satellite, then played them back
into the decoder later on).
Yep, the Astrid receiver I have is exactly like that - there's some TTL
in it which is used to drive the computer's serial port, plus sockets
for hook-up to a tape unit for recording.
That's what makes this other box that I have odd - the Astrid receiver
includes the necessary logic for interfacing to the CPU, and this other
box doesn't seem to have enough I/O lines to be for complex data
aquisition (such as imagery) - but I can't imagine what it's doing that
couldn't have just been done in software on the host computer.
I'm sure all will become clear when I get the time to trace the
schematic out!
Maplin sold PCBs (with silk-screen overlay) and
printed case panels IIRC.
This could be a homebrew copy, or it might (more likely) be another
magazine project.
the board's semi-professional, in that it looks to be low-volume, but
the lettering on it is all nicely done as are the marking giving
component locations etc. (plus I notice that the front and rear metal
panels are properly earthed, and the soldering's all good). Smells more
like something built-to-order in a small workshop (as was typical for
all sorts during the home computer boom I suppose!)
> I do have
a 'real' weather satellite receiver system. It came from
> ic.ac.uk, and the bit I really wanted (and got) were the 3 I2S image
[...]
I'd forgotten you had that. Do you have
sufficient software to make it
do something as a complete system if a suitable VAX were found, or has
Alas not. I got the I2S driver tape I think, but nothing more :-(
3:15 p.m.
New subject: Satellite stuff (Was: Re: BBC printer port (ever used for
Yep, the Astrid receiver I have is exactly like that -
there's some TTL
in it which is used to drive the computer's serial port, plus sockets
for hook-up to a tape unit for recording.
That's what makes this other box that I have odd - the Astrid receiver
includes the necessary logic for interfacing to the CPU, and this other
box doesn't seem to have enough I/O lines to be for complex data
aquisition (such as imagery) - but I can't imagine what it's doing that
couldn't have just been done in software on the host computer.
Yes, but rememebr back then that there were many incompatible host
computers (Beebs, Amstrad CPCs, Spectrums, C64setc, etc, etc) and that it
was common to keep the software to a minimum to make it easier to use the
device with just about every machine out there.
Alas not. I
got the I2S driver tape I think, but nothing more :-(
That's a shame. There must be a lot of big and complex systems that
would make interesting museum displays which have gone the same way due
to lack of software preservation :-( 
3:33 p.m.
New subject: Satellite stuff (Was: Re: BBC printer port (ever used foranything
any chance you can get a couple of photo's up somewhere of the board etc?
regards
charles
----- Original Message -----
From: "Jules Richardson" <julesrichardsonuk(a)yahoo.co.uk>
To: <cctalk(a)classiccmp.org>
Sent: Monday, September 20, 2004 11:18 PM
Subject: Re: Satellite stuff (Was: Re: BBC printer port (ever used
foranything
On Mon, 2004-09-20 at 05:40 +0100, Tony Duell wrote:
I will ahve to dig out the Maplin docs. IIRC that one had a 20 pin ribbon
cable which connected to a Beeb user port (or to a input port card for an
Amstrad CPC...)
Yes, I'm not quite sure what I have with this bit of kit. UoSAT offered
all sorts of telemetry though, so presumably this thing's designed to
filter out some specific data...
That's a shame. There must be a lot of big and complex systems that
would make interesting museum displays which have gone the same way due
to lack of software preservation :-(
cheers,
Jules
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.766 / Virus Database: 513 - Release Date: 18/09/2004
Right. The Maplin one (Published in the Maplin
Magazine) used only
the
user port IIRC.
I've got another one (decoder only) which looks very Maplin-ey. That
one
just has a pair of SPDT switches on the front along with a meter marked
0-10, whilst at the back there's just power, and a pair of DIN
sockets - The DIN sockets do sound Maplin-like, but I
thought they were on the
receiver. One linked to the decoder, the other to a tape recorder (you
recorded the analogue signals from the satellite, then played them back
into the decoder later on).
Yep, the Astrid receiver I have is exactly like that - there's some TTL
in it which is used to drive the computer's serial port, plus sockets
for hook-up to a tape unit for recording.
That's what makes this other box that I have odd - the Astrid receiver
includes the necessary logic for interfacing to the CPU, and this other
box doesn't seem to have enough I/O lines to be for complex data
aquisition (such as imagery) - but I can't imagine what it's doing that
couldn't have just been done in software on the host computer.
I'm sure all will become clear when I get the time to trace the
schematic out!
Maplin sold PCBs (with silk-screen overlay) and
printed case panels IIRC.
This could be a homebrew copy, or it might (more likely) be another
magazine project.
the board's semi-professional, in that it looks to be low-volume, but
the lettering on it is all nicely done as are the marking giving
component locations etc. (plus I notice that the front and rear metal
panels are properly earthed, and the soldering's all good). Smells more
like something built-to-order in a small workshop (as was typical for
all sorts during the home computer boom I suppose!)
> I do
have a 'real' weather satellite receiver system. It came from
> ic.ac.uk, and the bit I really wanted (and got) were the 3 I2S image
[...]
I'd forgotten you had that. Do you have
sufficient software to make it
do something as a complete system if a suitable VAX were found, or has
Alas not. I got the I2S driver tape I think, but nothing more :-(
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8 comments
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