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TM990/189 University Basic rom's

Ed Groenenberg

Experienced Member
Joined
Nov 14, 2018
Messages
137
Location
Bennekom, NL
Hello Everybody.

Recently I bought a TI TM990/189 SBC and I understand that there are 2 other Rom's (one 4Kb and one 2Kb) which
holds the software for University Basic.
My question is if someone has them and has the ability to program 2 eproms.

Contact me off-list if necessary.

Thanks,

Ed
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,114
Location
Seattle, WA
A few years back I found a "990189.zip" file somewhere online that contains a 2KB "990-469.u32" EPROM image and a 4KB "990-469.u33" image. I don't remember where I found that originally. Looking online now there are copies of it in the MESS ROM archives, for example the file here is identical to the file I originally found.

www.planetemu.net/rom/mess-roms/tm-990-189-university-board-microcomputer-with-university-basic

At the time I bought some TMS9902 Asynchronous Communication Controller chips and SN75188N Quad Line Driver chips to populate the optional serial port on the TM990/189 for use with the University Basic, but don't remember if I ever actually got around to programming some EPROMs and getting everything working. I'll have to dig out the gear and take a look.
 

Ed Groenenberg

Experienced Member
Joined
Nov 14, 2018
Messages
137
Location
Bennekom, NL
Ohh, seems my Google-fu is not so strong anymore. I just could not find those.
I downloaded them, just in case.

My TM990 has the UART on it and is configured for EIA, but the DB25 connector has never been placed on the board.
I have a proper angled one, so I can add it.

First I have to clean it in a bath of IPA, as it is having a thin layer of dust on it. Should come out as if it was new....
 

gslick

Veteran Member
Joined
Dec 30, 2010
Messages
2,114
Location
Seattle, WA
Hmm, I was going to see if I could finally get the University BASIC EPROMs running on a TM990/189 until I took a look at the schematic and realized that the U32 EPROM socket is set up for either TMS2708 or TMS2716 EPROMs. Those are triple voltage (+5, +12, -5) EPROMs, and are some of the few types of devices that my device programmer does not support. I suppose I could cut some traces on the PCB and rewire the U32 socket for standard 2716 EPROMs, but I'd rather not modify the PCB.

Some day I should pick up a Data I/O 29B or whatever is the best device programmer for those old triple voltage devices.
 

Ed Groenenberg

Experienced Member
Joined
Nov 14, 2018
Messages
137
Location
Bennekom, NL
A little sidenote / update, I got a set of connectors used for power and made a small PSU using a RT-50b unit and a plastic box I had lying around.
Works fine, total cost about Eur 30.
Next is to solder the angles DB25 connector and hook it up to the Teletype model 33 for extra fun.
 
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