Texas Instruments TMS1000

It was intended for embedded systems in automobiles, appliances, games, and measurement instruments.

[7] The Smithsonian Institution says TI engineers Gary Boone and Michael Cochran succeeded in creating the first microcontroller in 1971.

The TMS1000 family eventually included variants in both the original PMOS logic and also in NMOS and CMOS.

The ROM could not be altered in the field; the contents were fixed by the patterns laid down on the chip by the manufacturer.

Program ROM and data RAM were separately addressed as in a Harvard architecture; this became a typical characteristic of microcontrollers by many other manufacturers.

Some models had as few as 4 I/O lines because they had no on-chip ROM and the limited number of package pins were needed to access off-chip program memory.

Four input lines were provided for purposes such as sensing keyboard inputs, and a varying number of output lines were provided to control external devices, or to scan the rows of a keyboard matrix circuit.

All versions had a temperature range of 0 to 70 degrees C. Since these were intended as single-chip embedded systems, no special support chips (such as UARTs) were specifically made in the TMS 1000 family.