The Texas Instruments TI-99/4A

The TI99 was one of the first 16 bit machines and used the TMS9900 processor, which was also designed and built by Texas Instruments.

The TI99 was very well supported by TI with a large amount of add-ons, the draw back was the price with the cheapest at around £90, there were virtually no add-ons by third parties.

This machine never really caught on in the UK, but was widely used in schools in America and competed with the Apple as the most used micro in education   The photo above shows the TI with a speech synthesizer fitted, (right hand side)the synthesizer was inexpensive but could not work without either the extended basic or speech editor cartridge.

The Ti99 was built round the TMS9900 processor at a clock Speed of 1 MHz with a 26k ROM and 16k of  RAM and 8k of graphic ram, there are an extra 256 bytes of scratchpad ram not normally available to the user. these are used for the internal registers of the 9900, most CPU's have them built in

The Display is capable of  24 lines of 32 characters in 16 colours and graphics of 192 x 256 pixels in 2 colours.  The Interface's include, Cassette, Joystick, Monitor, Cartridge and Expansion bus