Questions tagged [ti-99]

For questions about the Texas Instruments TI-99 series of micro-computers, in particular the TI-99/4A.

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9
votes
2answers
1k views

Is it possible to use a TI-99/4A cassette cable with Digital Audio devices?

I would like to save and load BASIC programs with my TI-99/4A. The TI-99/4A can be connected to a cassette recorder for this purpose. Buying a cassette recorder and cassette tapes seems unnecessary ...
2
votes
0answers
120 views

How many units did TI Invaders sell?

I'm trying to get a feel for the scale and dynamics of the early home computer game industry. Statistics for arcade games and console cartridges are relatively easy to come by, e.g. that Pac-Man on ...
4
votes
1answer
323 views

Why did Extended BASIC on the TI-99/4A only allow 28 of the 32 sprites?

The Video Display Processor (VDP) of the TI-99/4A was capable of displaying 32 hardware sprites. These sprites were unusable with the default, built-in BASIC that TI provided. However, an enhanced ...
4
votes
1answer
756 views

What was the purpose of GROM (vs ROM) in the TI-99/4a?

The TI-99/4a had a cartridge slot on the front of the computer which accepted "solid state cartridges" (as TI called them). These cartridges would typically contain ROM (Read Only Memory) like many ...
17
votes
4answers
3k views

Why did the TI-99/4 have two databuses?

Wikipedia says on Russian page: Однако к 16-разрядной шине были подключены только 256 байт статической памяти и системное ПЗУ. Остальная память (ОЗУ) и периферийные устройства были 8-разрядными и ...
10
votes
2answers
1k views

How to fix a TI99/4a membrane keyboard?

I recently purchased a 1982 TI99/4a that has a defective keyboard. The keyboard is a Mitsumi with normal keys, but membrane type contacts. When I press the contacts (gently) with a plastic stylus ...