From Intellivision Wiki
General Instrument (GI) is the company that produced most of the electronics that go into the Intellivision. At the time, GI was based out of Hicksville, New York. GI was also the home of the PIC microcontroller. GI developed the PIC1640 and PIC1650 as an I/O coprocessors for the CP1610. (In a perhaps fitting twist, the Intellicart uses a Scenix SX52, which is a decendant of the original PIC.) GI spun off much of its microprocessor-related work (especially the PIC and speech-related products) as Arizona Microchip around 1985.
The Intellivision was based on GI's GIMINI 8900 game system that the company had developed. Mattel requested some extensions to the design, and thus the Intellivision was born. The two main extensions were:
Other than that, the initial Master Component was very, very similar to the original proposed GIMINI 8900 game system.