Language
Country/Area
No result found
From Farming to Home: What is the mysterious origin of the TRS-80 Color Computer?
The TRS-80 Color Computer, later renamed the Tandy Color Computer, is a series of home computers developed and sold by the Tandy Corporation. Despite sharing its name with the earlier TRS-80, the Color Computer was actually a completely different system and was based on the Motorola 6809E processor, which was very different from the previous Zilog Z80 model. This series of home computers was first launched in 1980 under the name Color Computer 1, followed by Color Computer 2 in 1983 and Color Computer 3 in 1986. There is a high degree of software and hardware compatibility between all three models, with almost no programs written on the old models not running on the new ones. Production of the Color Computer 3 ceased in 1991. All Color Computer models come with Color BASIC in ROM, an implementation of Microsoft BASIC. Third parties also offer multiple variants of the OS-9 multitasking operating system.
Historical background
Tandy Corporation announced the TRS-80 Color Computer in July 1980, aiming to provide a low-cost home computer. Color Computer's design is completely different from the Zilog Z80-based TRS-80 model. BYTE magazine once wrote: "The only similarity [between the two computers] is the name." The TRS-80 Color Computer originated from an experimental video text project in 1977 by the University of Kentucky Cooperative Extension Service and the University of Kentucky College of Agriculture. Motorola Semiconductor won the contract for the user terminals, and Tandy's computer division later became involved in manufacturing the terminals. The original intention of the project was to design a low-cost video text terminal to provide farmers, ranchers and other agricultural industry personnel with real-time information required for daily operations.
The Motorola MC6847 Video Display Generator (VDG) chip was released around the time the joint collaboration began. The 1978 "Green Thumb" terminal prototype used the MC6847 and Motorola 6809 microprocessors.
Color Computer 1 (1980–1983)
The original Color Computer had a large silver-gray case, a calculator-like CHICLET keyboard, and was available in 4K, 16K, or 32K memory options. Versions with at least 16K memory come with standard Microsoft Color BASIC or optional Extended Color BASIC. The early CoCo 1's only connection to a display device was to a TV. Early versions of the CoCo 1 had a black keyboard surround and the TRS-80 nameplate on the left side of the keyboard. Later versions removed the black keyboard surround and RAM buttons, and moved the TRS-80 logo to the centerline of the case.
Radio Shack can upgrade all versions equipped with standard Color BASIC to Extended Color BASIC, the developer is Microsoft.
Color Computer 2 (1983–1986)
During the initial CoCo 1 production, many of the support circuits had been redesigned into a handful of custom integrated circuits, so the CoCo 1's circuit board was mostly blank. To reduce production costs, the casing was shortened by about 25%, and the power supply and motherboard were redesigned to be smaller. CoCo 2 is sold in 16K and 64K models and is compatible with previous generation devices. With the improvement of ROM, new functions and fixed bugs make the system have higher performance and usability.
Color Computer 3 (1986–1991)
By 1985, Color Computer users were worried that the company would abandon the computer in favor of the Tandy 1000. Tandy executive Ed Juge promises that Color Computer's potential is unparalleled. On July 30, 1986, Tandy announced Color Computer 3 at the Waldorf Astoria Hotel in New York City. This model provides 128KB of RAM and can be upgraded to 512KB, with higher performance and diverse visual output functions.
CoCo 3 has strong compatibility, not only supports most older versions of software, but also works well with CoCo 2 peripherals.
Hardware architecture
The CoCo 1 and CoCo 2 models are almost functionally identical and are mainly composed of multiple LSI chips, including MC6809E microprocessor, MC6883/SN74LS783/SN74LS785 synchronous address multiplexer (SAM) and MC6847 video display generator (VDG) . SAM is responsible for clock control, synchronization and memory management, while VDG is used for graphics display and supports display capabilities in multiple modes.
The journey of TRS-80 Color Computer started from the needs of agricultural projects and finally entered the home computer market. Does this process reflect the close connection between technology and daily life?
