A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (PCB). Microcomputers became popular in the 1970s and 1980s with the advent of increasingly powerful microprocessors. The predecessors to these computers, mainframes and minicomputers, were comparatively much larger and more expensive. Many microcomputers are also personal computers. An early use of the term "personal computer" in 1962 predates microprocessor-based designs. (See "Personal Computer: Computers at Companies" reference below). A "microcomputer" used as an embedded control system may have no human-readable input and output devices. "Personal computer" may be used generically or may denote an IBM PC compatible machine.
The Intel MCS-51 is a single chip microcontroller (MCU) series developed by Intel in 1980 for use in embedded systems. The architect of the Intel MCS-51 instruction set was John H. Wharton. Intel's original versions were popular in the 1980s and early 1990s, and enhanced binary compatible derivatives remain popular today. It is a complex instruction set computer, but also has some of the features of RISC architectures, such as a large register set and register windows, and has separate memory spaces for program instructions and data.
The MCS-48 microcontroller series, Intel's first microcontroller, was originally released in 1976. Its first members were 8048, 8035 and 8748. The 8048 is probably the most prominent member of the family. Initially, this family was produced using NMOS technology. In the early 1980s, it became available in CMOS technology. It was manufactured into the 1990s to support older designs that still used it.
The Intel 8008 is an early byte-oriented microprocessor designed by Computer Terminal Corporation (CTC), implemented and manufactured by Intel, and introduced in April 1972. It is an 8-bit CPU with an external 14-bit address bus that could address 16 KB of memory. Originally known as the 1201, the chip was commissioned by Computer Terminal Corporation (CTC) to implement an instruction set of their design for their Datapoint 2200 programmable terminal. As the chip was delayed and did not meet CTC's performance goals, the 2200 ended up using CTC's own TTL-based CPU instead. An agreement permitted Intel to market the chip to other customers after Seiko expressed an interest in using it for a calculator.
The Nascom 1 and 2 were single-board computer kits issued in the United Kingdom in 1977 and 1979, respectively, based on the Zilog Z80 and including a keyboard and video interface, a serial port that could be used to store data on a tape cassette using the Kansas City standard, and two 8-bit parallel ports. At that time, including a full keyboard and video display interface was uncommon, as most microcomputer kits were then delivered with only a hexadecimal keypad and seven-segment display. To minimize cost, the buyer had to assemble a Nascom by hand-soldering about 3,000 joints on the single circuit board. Later on, a pre-built, cased machine named Nascom 3 was available; this used the Nascom 2 board.
The Intel 8085 ("eighty-eighty-five") is an 8-bit microprocessor produced by Intel and introduced in March 1976. It is software-binary compatible with the more-famous Intel 8080 with only two minor instructions added to support its added interrupt and serial input/output features. However, it requires less support circuitry, allowing simpler and less expensive microcomputer systems to be built. The "5" in the part number highlighted the fact that the 8085 uses a single +5-volt (V) power supply by using depletion-mode transistors, rather than requiring the +5 V, −5 V and +12 V supplies needed by the 8080. This capability matched that of the competing Z80, a popular 8080-derived CPU introduced the year before. These processors could be used in computers running the CP/M operating system.
The KIM-1, short for Keyboard Input Monitor, is a small 6502-based single-board computer developed and produced by MOS Technology, Inc. and launched in 1976. It was very successful in that period, due to its low price and easy-access expandability.
The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. Sold for US$60, it was the first commercially produced microprocessor, and the first in a long line of Intel CPUs.
The Intel 4040 microprocessor was the successor to the Intel 4004. It was introduced in 1974. The 4040 employed a 10 μm silicon gate enhancement load PMOS technology, was made up of 3,000 transistors and could execute approximately 62,000 instructions per second. General performance, bus layout and instruction set was identical to the 4004, with the main improvements being in the addition of extra lines and instructions to recognise and service interrupts and hardware Halt/Stop commands, an extended internal stack and general-purpose "Index" register space to handle nesting of several subroutines and/or interrupts, plus a doubling of program ROM address range.
The Big Board (1980) and Big Board II (1982) were Z80 based single-board computers designed by Jim Ferguson. They provided a complete CP/M compatible computer system on a single printed circuit board, including CPU, memory, disk drive interface, keyboard and video monitor interface. The printed circuit board was sized to match the Shugart 801 or 851 floppy drive. This allowed attachment to up to two 8 inch or 5 1/4 inch floppy disk drives. The Big Board II added a SASI interface which could be used to drive hard drives, enhancements to system speed and enhancements to the terminal interface.
The Xerox 820 Information Processor is an 8-bit desktop computer sold by Xerox in the early 1980s. The computer runs under the CP/M operating system and uses floppy disk drives for mass storage. The microprocessor board is a licensed variant of the Big Board computer.
The Netronics ELF II was an early microcomputer trainer kit featuring the RCA 1802 microprocessor, 256 bytes of RAM, DMA-based bitmap graphics, hexadecimal keypad, two digit hexadecimal LED display, a single "Q" LED, and 5 expansion slots. The system was developed and sold by Netronics Research and Development Limited in New Milford, CT, USA.
The Fairchild F8 is an 8-bit microprocessor system from Fairchild Semiconductor, announced in 1974 and shipped in 1975. The original processor family included four main 40-pin integrated circuits (ICs); the 3850 CPU which was the arithmetic logic unit, the 3851 Program Storage Unit (PSU) which contained 1 KB of program ROM and handled instruction decoding, and the optional 3852 Dynamic Memory Interface (DMI) or 3853 Static Memory Interface (SMI) to control additional RAM or ROM holding the user programs or data. The 3854 DMA was another optional system that added direct memory access into the RAM controlled by the 3852.
The Tangerine Microtan 65 was a 6502 based single board microcomputer, first sold in 1979, which could be expanded into, what was for its day, a comprehensive and powerful system. The design became the basis for what later became the ORIC ATMOS and later computers, which has similar keyboard addressing and tape I/O as in the Microtan 65. The Microtan 65 has a single step function that can be used for debugging at the hardware level. The computer was available as ready-built boards or as kits consisting of board and components requiring soldering together.
A microprocessor development board is a printed circuit board containing a microprocessor and the minimal support logic needed for an electronic engineer or any person who wants 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.
The Dick Smith Super-80 was a Zilog Z80 based kit computer developed as a joint venture between Electronics Australia magazine and Dick Smith Electronics.
The LINK 480Z was an 8-bit microcomputer produced by Research Machines Limited in Oxford, England, during the early 1980s.
A single-board microcontroller is a microcontroller built onto a single printed circuit board. This board provides all of the circuitry necessary for a useful control task: a microprocessor, I/O circuits, a clock generator, RAM, stored program memory and any necessary support ICs. The intention is that the board is immediately useful to an application developer, without requiring them to spend time and effort to develop controller hardware.
The P8000 is a microcomputer system developed in 1987 by the VEB Elektro-Apparate-Werke Berlin-Treptow „Friedrich Ebert“ (EAW) in the German Democratic Republic. It consisted of an 8-bit and a 16-bit microprocessor and a Winchester disk controller. It was intended as a universal programming and development system for multi-user/multi-task applications. The initial list price of the P8000 was 172,125 East German marks.
The Gigatron TTL is a retro-style 8-bit computer, where the CPU is implemented by a set of TTL chips instead of a single microprocessor, imitating the hardware present in early arcades. Its target is the computing enthusiasts, for studying or hobby purposes.
