Intel 4004
| File:L Intel-C4004 (gray traces).jpg A rare gold-white-gray Intel C4004 microprocessor | |
| General information | |
|---|---|
| Launched | late 1971 |
| Discontinued | 1974 |
| Common manufacturer |
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| Performance | |
| Max. CPU clock rate | 740 kHz |
| Architecture and classification | |
| Instruction set | pre x86 |
| Physical specifications | |
| Socket |
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The Intel 4004, a 4-bit central processing unit (CPU) released by Intel Corp. in 1971, is widely considered to be the world's first commercial single-chip microprocessor.[1] The 4004 employed a silicon NMOS technology.
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 (later of ZiLOG).
Originally designed for the Japanese company Busicom to be used in their line of calculators (instead of the complex special purpose calculator chipset that Busicom had designed themselves and brought to Intel to have made, which Intel determined was too complex to make with the technology they had at the time), the 4004 was also provided with a family of custom support chips (e.g., each "Program ROM" internally latched for its own use the 4004's 12-bit program address, which allowed 4 KB memory access from the 4-bit address bus if all 16 ROMs were installed). 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 (and the 4040, a revised 4004).
As its fourth entry in the microprocessor market, Intel released the CPU that started the microcomputer revolution — the 8080.
On the 15 November 2006, the 35th anniversary of the Intel 4004, Intel celebrated by releasing the chip's schematics, maskworks, and user manual.
Technical specifications
- Maximum clock speed is 740 kHz[2]
- Separate program and data storage (i.e., a Harvard architecture). 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 (of which 41 are 8 bits wide and 5 are 16 bits wide)
- 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.
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Custom support chips
- 4001: 256-byte ROM (256 8-bit program instructions), and one built-in 4-bit I/O port[3]
- 4002: 40-byte RAM (80 4-bit data words), and one built-in 4-bit output port; the RAM portion of the chip is organized into four "registers" of twenty 4-bit 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[3]
- 4009: program and I/O access converter to standard memory and I/O chips[3]
Collectability
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 (the original package type). 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
- ^ In 1970, over a year prior to the introduction of the 4004, the single-chip military F14 CADC microprocessor was deployed, though its existence remained classified until 1998. David A. Patterson, however, argues that the F14 CADC should not be considered a microprocessor in the modern sense and instead a "microprogrammed special purpose computer, using a variable number of custom chips." Patterson, Dave (September 25, 1998). "The F-14A Central Air Data Computer MP944 Microprocessor". Retrieved 2006-05-20.
- ^ All of Intel's 4004 data sheets, including the very first data sheet from November 1971, clearly indicate that the minimum clock period is 1350 nanoseconds, which results in a maximum clock speed of 740 kHz. Unfortunately, many apparently reputable web pages and other sources list an incorrect clock speed of 108 kHz; even Intel's own pages on the 4004's history say this. The 4004's minimum instruction cycle time is 10.8 microseconds (8 clock cycles), and it seems most likely that someone in the past confused this with a clock speed. This error has now propagated very widely.
- ^ a b c a 4001 ROM+I/O chip cannot be used in a system along with a 4008/4009 pair.
External links
- Intel's First Microprocessor—the Intel® 4004 — Intel Museum (Intel Corporate Archives) entry.
- The Intel 4004: A testimonial from Federico Faggin, its designer, on the first microprocessor's thirtieth birthday — Faggin's own 4004 website.
- Interview with Masatoshi Shima regarding his role in the 4004 — at the IEEE's History Center.
- MCS-4 Micro Computer Set Data Sheet (12 pp.) — Intel Corp., November 1971; at the Smithsonian's Chip Collection.
- Comprehensive Intel 4004 chipset information — at Christian Bassow's CPU Museum.
- Intel 4004 chip collecting information — at The Antique Chip Collector's Page.
- Intel 4004 schematics — at the unofficial 4004 website.