A microcomputer is a small computer with a microprocessor as the basic central processing unit (CPU). It consists of a microprocessor and peripheral devices (memory and input/output circuits) mounted on a single PCB. The term microcomputer is most commonly associated with the first wave (in the 1970s and 1980s) of all-in-one 8-bit home and small business computers. For example the Tandy TRS-80, Apple II, Atari 800, Sinclair ZX81, Commodore 64 and so on.
The first microprocessors used for this purpose were developed in the early 1970s and were first used for electronic calculators. Affordable 8-bit microprocessors with 16-bit addressing also led to the first general-purpose microcomputers in the mid-1970s.
Later the development went on the one hand towards PC (personal computer) and on the other hand towards microcontroller (with memory and peripherals on-chip) for embedded systems.
The microcomputer building blocks that accompanied my personal career are shown below.
Intel D8080A CPU family: 8080A Inertial release: 1974 Variante: 1979 Production year: 1985 TD: 8 bit, 2 MHz, 64 kB Transistors: ∼5000 Package: CERDIP40 |
Zilog Z8400A CPU family: Z80 Inertial release: 1976 Production year: 1983 TD: 8 bit, 4 MHz, 64 kB Transistors: ∼8500 Package: PDIP40 |
Signetics SCN2650A CPU family: 2650 Inertial release: 1975 Production year: 1985 TD: 8b, 1.25 MHz, 32 kB Package: PDIP40 |
Rockwell R6502AP CPU family: 6800 Inertial release: 1975 Production year: 1984 TD 8 bit, 2 MHz, 64 kB Package: PDIP40 |
National INS8060N CPU family: SC/MP II Inertial release: 1977 Production year: 1984 TD: 8 bit, 4 MHz, 64 kB Package: PDIP40 |
OKI M80C85A CPU family: 8085 Inertial release: 1976 Production year: 1982 TD: 8 bit, 3 MHz, 64 kB Transistors: ∼6500 Package: PDIP40 |
Zilog Z0840006PSC CPU family: Z80 Inertial release: 1988 Production year: 1988 TD: 8 bit, 6 MHz, 64 kB Package: PDIP40 |
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Intel TD87C51 Microcontoller CPU family: 8751 On-Chip: 4k EPROM 128b RAM I/O, Timer/Clock Inertial release: 1986 Production year: ? TD: 8b, 12 MHz, 128 kB Package: CERDIP40 |
Intel LP87C51 Microcontoller CPU family: 8751 On-Chip: 32 I/O ports Serial port 4k OTP ROM 128kb RAM I/O, Timer/Clock Inertial release: 198x Production year: ? TD: 8b, 12 MHz, 128 kB Package: PDIP40 |
S188 B Siemens Package: CERDIP40 Unknown chip. If you recognize the S188B, please contact me! |
 B8238 NEC System Controller |
 SY6545A-1 Synertek CRT Contr. |
 SYP1793-002 Synertek FDC |
 EF6821P Thomson PIA |
 Z8440A Zilog SIO |
 R6522P Rockwell VIA |
 Z8530A AMD SIO |
 Z0843006P Zilog Counter/Timer |
 P8259A Intel Interrupt Contr. |
 HD46505SP Hitachi CRT Contr. |
 RAM |
 PROM |
 EPROM 16k |
 EPROM 16k |
 EPROM 32k |
 EPROM 64k |
 EPROM 256k |
