Microprocessor development board

A microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an engineer to become acquainted with the microprocessor on the board and to learn to program it. It also served users of the microprocessor as a method to prototype applications in products.

Unlike a general-purpose system such as a home computer, usually a development board contains little or no hardware dedicated to a user interface. It will have some provision to accept and run a user-supplied program, such as downloading a program through a serial port to flash memory, or some form of programmable memory in a socket in earlier systems.

The reason for the existence of a development board was solely to provide a system for learning to use a new microprocessor, not for entertainment. So everything superfluous was left out to keep costs down. Even an enclosure was not supplied, nor a power supply. This is because the board would only be used in a "laboratory" environment so it did not need an enclosure, and the board could be powered by a typical bench power supply already available to an electronic engineer.

Microprocessor training development kits were not always produced by microprocessor manufacturers. Many systems that can be classified as microprocessor development kits were produced by third parties, one example is the Sinclair MK14, which was inspired by the official SC/MP development board from National Semiconductor, the "NS introkit".

Although these development boards were not designed for hobbyists, they were often bought by them because they were the earliest cheap microcomputer devices you could buy. They often added all kinds of expansions, such as more memory, a video interface etc. It was very popular to use (or write) an implementation of Tiny Basic. The most popular microprocessor board, the KIM-1, received the most attention from the hobby community, because it was much cheaper than most other development boards, and you could get more software for it (Tiny Basic, games, assemblers), and cheap expansion cards to add more memory or other functionality. More articles were published in magazines like "Kilobaud Microcomputing" that described home-brew software and hardware for the KIM-1 than for other development boards.

...
Wikipedia