Editing TMS9900 (section)

==Applications==
[[File:Tomy-Tutor-wControllers.jpg|link=File:Tomy-Tutor-wControllers.jpg|thumb|The [[Tomy Tutor]], a 1983 home computer based on the TMS9995 processor]]

The TMS9900 was used in the [[TI-99/4A|TI-99/4 and TI-99/4A]] home computers. Unfortunately, to reduce the production costs, TI chose to use  just 256 bytes (128 16-bit words) of the fast kind of RAM that the TMS9900 could access directly. The rest of the memory was 16 KB of [[8-bit]] [[Dynamic random access memory|DRAM]] that was accessible only indirectly through the video display controller, which crippled the performance of these machines.

TI developed the TM990 series of computer modules, including CPU, memory, and I/O, which, when plugged into a card frame, could form a 16-bit minicomputer. These were typically used for process control.<ref>{{cite web | url=http://www.stuartconner.me.uk/tm990/tm990.htm | title=Stuart's TM 990 Series 16-Bit Microcomputer Modules| access-date=2014-03-25}}</ref> A microprocessor trainer was released in the form of the TM990/189.<ref>{{cite web | url=http://www.rskey.org/CMS/index.php/exhibit-hall/118-texas-instruments-tm-990189 | title=Programmable Calculators - Texas Instruments TM990/189| access-date=2014-03-25}}</ref>

In the late 1970s, [[John_Walker_(programmer) | John Walker]] and Dan Drake developed [[S-100_bus | S100-bus cards]] based on the TMS9900 and a full software stack to go with it.<ref>{{cite web | url=https://www.fourmilab.ch/documents/marinchip/ | title=Marinchip Systems history | access-date=2024-08-25}}</ref><ref>{{cite web | url=https://gitlab.com/marinchip | title=Marinchip software | access-date=2024-08-25}}</ref> They later went on to be co-founders of [[Autodesk]], which was in part based on software first developed for these TMS9900 based systems.<ref>{{cite web | url=https://www.shapr3d.com/history-of-cad/autodesk-and-autocad | title=Autocad history | access-date=2024-08-25}}</ref>