The TRS-80 Color Computer, often referred to as CoCo by its users, started out as a joint venture between Fort Worth based Tandy Corporation and (then) Austin based Motorola Semiconductor, Inc. to develop a low cost home computer in 1977.
The initial goal of this project, called "Green Thumb", was to create a low cost VideoTex terminal for farmers, ranchers, and others in the agricultural industry. This terminal would connect to a phone line and an ordinary color TV and allow the user access to near real-time information useful to their day to day operations on the farm.
Motorola's MC6847 Video Display Generator (VDG) chip was released about the same time as the joint venture started and it has been speculated that the VDG was actually designed for this project. At the core of the prototype "Green Thumb" terminal, the MC6847, along with the MC6808 Microprocessor Unit (MPU), made the prototype a reality by about 1978. Unfortunately the prototype contained too many chips to be commercially viable. Motorola solved this problem by integrating all the functions of the many smaller chips into one chip, the MC6883 Synchronous Address Multiplexer (SAM). By that time in late 1979, the new and powerful Motorola MC6809 processor was released and, together, the SAM, VDG, and 6809 are combined. The AgVision terminal is born.