Intel 4004
The Intel 4004, a 4-bit
central processing unit released by
Intel Corp. in 1971, is widely considered to be the world's first commercial single-
chip microprocessor.
While often credited with jump-starting the microprocessor and microcomputer industries, other
integrated circuit manufacturers were already developing similar devices independently at the time. As for the 4004 itself, it was largely a commercial failure and had very little impact on the electronics industry as a whole.
Encyclopedia
The
Intel 4004, a 4-bit
central processing unit released by
Intel Corp. in 1971, is widely considered to be the world's first commercial single-
chip microprocessor.
While often credited with jump-starting the microprocessor and microcomputer industries, other
integrated circuit manufacturers were already developing similar devices independently at the time. As for the 4004 itself, it was largely a commercial failure and had very little impact on the electronics industry as a whole.
History and description
The 4004 was released in 16-pin
CERDIP packaging on November 15th, 1971. The 4004 is the first computer processor designed and manufactured by
chip maker
Intel, which previously made
semiconductor memory chips. The chief designers of the chip were Ted Hoff and
Federico Faggin of Intel and Masatoshi Shima of Busicom .
Originally designed for the
Japanese company Busicom to be used in their line of
calculators , the 4004 was also provided with a family of custom support chips . The 4004 circuit was built of 2,300
transistors, and was followed the next year by the first ever 8-bit microprocessor, the 3,300 transistor
8008 .
As its fourth entry in the microprocessor market, Intel released the CPU that started the
microcomputer revolution — the
8080.
Technical specifications
- Maximum clock speed is 740 kHz
- Separate program and data storage . Contrary to most Harvard architecture designs, however, which use separate buses, the 4004, with its need to keep pin count down, uses a single multiplexed 4-bit bus for transferring:
- 12-bit addresses
- 8-bit instructions
- 4-bit data words
- Instruction set contains 46 instructions
- Register set contains 16 registers of 4 bits each
- Internal subroutine stack is 3 levels deep
Microarchitecture and pinout
Click the pictures to view the full-size versions.
Custom support chips
- 4001: 256-byte ROM , and one built-in 4-bit I/O port
- 4002: 40-byte RAM , and one built-in 4-bit output port; the RAM portion of the chip is organized into four "registers" of twenty 4-bit words:
- 16 data words
- 4 status words
- 4003: 10-bit parallel output shift register for scanning keyboards, displays, printers, etc.
- 4008: 8-bit address latch for access to standard memory chips, and one built-in 4-bit chip select and I/O port: program and I/O access converter to standard memory and I/O chipsllectability
The Intel 4004, naturally, is one of world's most sought-after collectable/antique chips. Of highest value are 4004s that are gold and white, with visible so called 'grey traces' on the white portion . As of 2006, such chips reached around US$1000 each on eBay. The slightly less valuable white and gold chips without grey traces typically reach $300 to $500. Those chips without a 'date code' underneath are earlier versions, and therefore worth slightly more. Other valuable chips include the Intel 4040.
Notes
External links
- – Faggin's own 4004 website
- – At the IEEE's History Center pages
- – Intel Corp., November 1971; At the Smithsonian's Chip Collection website
- – At Christian Bassow's CPU Museum
- – At The Antique Chip Collector's Page
