TM990 / 189
TM990 / 189 Microcomputer ( 1979)
The TM990/189 is a self- contained, single board microcomputer system. It is intended for use as a learning aid in
instruction of microcomputer fundamentals, machine and assembly language programming, and microcomputer
interfacing. It also demostrates TMS 9900 family applications and advanteges.
- TMS9980a microprocessor
-1024 bytes RAM
- 4096 bytes ROM
- 2 mhz oscillator
- audio cassette interfaces
- 16 biti I/O programmable
- 45 key alphanumeric keyboard
- Ten-digit, sevn-segment led
- Visual and acoustic indicators
- TMS9902 asynchronous communication controllers
In the various events we attended, we were able to put a TM990 / 189 into operation. The main feature is to have a Basic interpreter on board, and to interface it with the Travelmate 560 via the RS232 serial. Programs are read and written via a recorder for the TI-99/4A PHP-2700.
The program loaded via laptop is a small program to generate a clock with hours, minutes and seconds.
The TM 990/301 Microterminal was introduced in 1978 as a small console for the TMS9900 based computer system TM
990/100M. This Microterminal is obviously based on a normal TI-30, the most successful scientific calculator of that time frame.
Dismantling the TM 990/301 Microterminal discovers a completely different internal construction. Instead the small printed circuit board (PCB) of the TI-30 and all the other calculators using its housing we notice a big PCB based on a TMS1000 single-chip
microcomputer. Remember that the TMS1000 is still recognized as the first true microcomputer and found its way into millions of products. A similar approach using a standard calculator housing for industrial products could be found with the TI-510 PLC Programmer.
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