IEEE-488 card with TMS9914A controller

[+FarmerPotato]

cbmeeks accidentally spoke the name of the IEEE-488 card, which got me thinking.

 

IEEE-488 is a communications standard also known as GPIB. (General Purpose Instruments Bus.)

It was commonly used to connect electronics test and laboratory equipment. Commodore PET used it as a peripheral bus.

 

TI made a lot of GPIB gear, especially the one-chip TMS9914A controller. They designed a GPIB card for the TI-99/4A, but it was not marketed.

 

The schematic for the TI-99/4A IEEE-488 card is here: http://www.mainbyte.com/ti99/schematic/ieee488.jpg

It contains a DSR. It contains a PAL, however its used for only 4 output signals which are pretty obvious.

Here is the TI manual for the TMS9914A controller chip: http://bitsavers.trailing-edge.com/components/ti/TMS9900/TMS9914A_General_Purpose_Interface_Bus_Controller_Data_Manual_Dec82.pdf

The first product of National Instruments was a GPIB card for the PDP-11. (Not to be confused with TI.. NI made an employee T-shirt saying "National Instruments--Not Selling Calculators since 1976.") NI had a second source or clone chip, NAT9914, pin compatible with TMS9914A controller.

http://www.ni.com/pdf/manuals/372013b.pdf

 

I have a pile of GPIB bus testers in my garage with NAT9914 chips. I'm not sure if I have any actually useful GPIB devices. You can still get TMS9914A from China surplus.

Here is a Dr Dobbs article on making a GPIB: http://www.drdobbs.com/embedded-systems/implementing-the-gpib/184408548

 

I'm not saying I actually want a GPIB card, just collecting together the puzzle pieces here.

Edited February 8, 2019 by FarmerPotato

[peterfleeman]

I want one!

[+OLD CS1]

I have two Amiga Zorro cards with these chips.

[+Lee Stewart]

... IEEE-488 is a communications standard also known as GPIB. (General Purpose Instruments Bus.)

It was commonly used to connect electronics test and laboratory equipment. ...

 

Though it was used first and foremost for interfacing scientific instruments, the ‘I’ of GPIB actually stands for “Interface”. Hewlett-Packard developed the interface specification for interfacing its scientific instruments with each other and data-processing/reporting devices and named it the Hewlett-Packard Interface Bus or HPIB. After it caught on with other manufacturers, who, quite naturally, did not want “Hewlett-Packard” in the name/description of their equipment, it then became known also as the General Purpose Interface Bus or GPIB. Over the course of my career as, principally, an analytical chemist, I used a lot of scientific instruments whose components were tied together with this interface.

 

...lee

[+9640News]

also as the General Purpose Interface Bus or GPIB. Over the course of my career as, principally, an analytical chemist, I used a lot of scientific instruments whose components were tied together with this interface.

 

...lee

 

Agilent or HP 5890 perhaps?

[+Lee Stewart]

Agilent or HP 5890 perhaps?

 

For sure. I do not remember exactly when instruments using IEEE 488 interfacing came to the lab in which I worked, but I remember the interface specs from the late 1970s.

 

I very much remember working with another interface, a 50-pin parallel BCD interface, on an HP 97S calculator, among other equipment, in the late 1970s through the 1980s.

 

These all quickly gave way to RS232C due to much smaller connectors, much thinner cabling and much, much longer allowable distances between components. This scenario continues with Ethernet, etc., but I digress ...

 

...lee

[+Ksarul]

There is a version of the schematic here in the schematics thread too, so you can get a nice clear print of both versions of the TI board (yes, there were two variants). Those schematics also have the equations for the PAL, so you just need to resynthesize them to get the proper JEDEC file to program a chip. . .

 

There were also quite a few printers with an IEEE interface, and as the bus supported multiple masters, you could also use it to interface computers in a simple workgroup using the same peripheral equipment.

[jbdigriz]

On 2/8/2019 at 5:59 PM, FarmerPotato said:

The schematic for the TI-99/4A IEEE-488 card is here: http://www.mainbyte.com/ti99/schematic/ieee488.jpg

It contains a DSR. It contains a PAL, however its used for only 4 output signals which are pretty obvious.

 

 

I believe there is a rev. 1 and a rev. 2 of this card. Are there dumps available of the DSR ROM for either, and for completeness, was there a standalone version?

[+Ksarul]

21 hours ago, jbdigriz said:

I believe there is a rev. 1 and a rev. 2 of this card. Are there dumps available of the DSR ROM for either, and for completeness, was there a standalone version?

The main differences between the two versions were the type of EPROM chip used, IIRC from my work to redo the schematics, both are in the schematics thread, but here they are again.

A3-IEEE-488-P1b.pdf A3-IEEE-488-P2b.pdf

[jbdigriz]

Thanks! And is there a ROM dump anywhere?

[+Ksarul]

I may have to open one of mine up to do a dump of the ROM. I'll see if I can pull one of the two I have out sometime in the near future. Also, on the W1/W2 jumpers, normally W2 (to ground) is connected.

 

One other note: I thought I had seen the PAL equations somewhere, but they are not in the manual or with the schematics I have. The manual on WHT is also incomplete, as the programming appendices are missing.

[+FarmerPotato]

On 2/9/2019 at 1:34 PM, Ksarul said:

There is a version of the schematic here in the schematics thread too, so you can get a nice clear print of both versions of the TI board (yes, there were two variants). Those schematics also have the equations for the PAL, so you just need to resynthesize them to get the proper JEDEC file to program a chip. . .

 

There were also quite a few printers with an IEEE interface, and as the bus supported multiple masters, you could also use it to interface computers in a simple workgroup using the same peripheral equipment.

I've never worked with an instrument that was GPIB exclusively. 

 

So GPIB or IEEE-488 remaind just a curiosity. Curious, in that I have several computers with GPIB controller-card, but no peripherals to connect to them!

 

When I was a teenager, I would notice HP plotters in universities and elsewhere. I guess these were the HP-7470, 7475, or HP-7440A types.  My high school had a donated one, with working pens. 

 

My brother spent a lot of effort using one of those, using Extended Basic to plot conic sections, by sending HPGL. But, it had the RS232 port. Almost everything I come across from the 80s has RS232. (With that plotter, my brother made parabolic dishes.)

 

If I had a 99/4A IEEE-488 card, and a scope with GPIB option, I think it would be amusing to "close the loop". Use it to capture the PEB bus signals and display them in bitmap mode.  This would require a logic analyzer, or at least a sampling scope. I have a little experience programming their descendants, that standardized on VISA, SCPI, etc sequences.

 

"Closing the loop" would just be a neat trick, since the tools to do that job are already on my desk.
 

 

[+mizapf]

For some seconds (as we have schematics), I thought this could be easily emulated in MAME, but I guess it would not make too much sense. I would also have to emulate devices that connect to that card.

[+Lee Stewart]

1 hour ago, FarmerPotato said:

I've never worked with an instrument that was GPIB exclusively.

 

A lot of scientific instruments I used in my career as a biochemist and analytical chemist had IEEE-488 interfaces. Most of them were HP scientific equipment. HP used it to interface various components of a single instrument as well as to network instruments. Since HP developed the bus, it was called the HPIB (Hewlett-Packard Interface Bus). It was only later, after inclusion in a few standards, that it was called the GPIB (General Purpose Interface Bus).

 

...lee