History of the 4004 Development

Federico Faggin (Designer of the 4004 CPU)
Japanese calculator company, Busicom
World's First Microcomputer
A Brief Microprocessor History

Federico Faggin (Designer of the 4004 CPU)

The 4004, the world's first microprocessor, is signed with the initials F.F., for Federico Faggin, its designer. Signing the chip was a spontaneous gesture of proud authorship. It was also an original idea, imitated after him by others. Faggin initially etched the F.F. inside the design. Later he moved them to its border, like the autograph on a work of art. The signature is a particularly poignant testimony because, at the time of its birth, the first microprocessor, far from being considered a milestone by Intel's management, represented a diversion from the mainline business of the company which was memory chips.

The birth of the 4004 was an intense moment witnessed by Faggin alone, working into the night in the deserted Intel labs. He had received the 4004 wafers from the manufacturing line at around 6 PM, in January 1971, as people were leaving for the day. With hands trembling and heart pounding he loaded the wafers in the wafer prober and connected it to the tester. A sigh of relief raised from his chest, above the humming of the instruments, as he observed electrical activity in the device. As the testing progressed, the tension was gradually transforming into elation as all the critical functions showed to be operating properly. At around 3 AM, exhausted and ecstatic, Faggin left the lab. At home his wife, Elvia, was waiting for the news. "It works"! he announced, and they shared the happiness in this moment of triumph.

Federico Faggin signed the 4004 because:

• He was the leader of the design/development project of the first microprocessor, and brought it to its successful conclusion.
• Faggin did the detailed design work (logic design, circuit design, chip layout, tester design and test program development) with help from Masatoshi Shima, a Busicom engineer.
  Busicom presented to Faggin, as the leader of the project, their prototype calculator with the 4004. Faggin in 1996 donated it to the Computer History Museum in Silicon Valley.
• He was the original developer of the Silicon Gate Technology, the first commercial self-aligned gate process, and the designer of the world's first commercial integrated circuit using the silicon gate technology: the Fairchild 3708. This semiconductor technology was copied by Intel and made into its core manufacturing technology, enabling the early realization of high-performance memories and the microprocessor.
• Faggin made two other key inventions at Fairchild: the Buried Contact and the Bootstrap Load. At Intel he applied these innovations to build the first microprocessor. They were essential in making the 4004 a reality with the technology available in 1970. Faggin also created the basic Methodology of Random Logic Design using silicon gate technology. This methodology did not exist at Intel or anywhere else until he developed it in 1970. It set the style of design used for all early generations of microprocessors at Intel.
• He demostrated that the 4004 could be used for applications other than calculators and vigorously campaigned inside Intel to make the 4004 available to the general market.

Two patents cover Intel's first microprocessor: patent no. 3,821,715, Memory System for a Multi-Chip Digital Computer, in the names of Ted Hoff, Stan Mazor and Federico Faggin; and patent no. 3,753,011, power supply settable, bi-stable circuit, in the name of Federico Faggin.

Faggin left Intel in 1974, to start Zilog, a company dedicated to the emerging microprocessor market and a direct competitor of Intel. After having led from the beginning all of Intel's microprocessor development activity, at the time of his leaving Faggin was heading all of the MOS chip design activity, with the exception of dynamic memories. Intel’s management punished Faggin by disowning him of his many contributions, attributing most of his credits in the creation of the microprocessor to Ted Hoff, and by encouraging lesser contributors to grab a bigger share and play a bigger role than they did to diminish Faggin's legacy.

Japanese calculator company, Busicom

Former Intel engineers and microprocessor co-inventors (left to right) Stan Mazor, Federico Faggin and Ted Hoff.	In 1969, Japanese calculator company, Busicom, needed reprogrammability and small size and asked Intel to create a solution. Intel assigned engineers Federico Faggin, Marcian E. (Ted) Hoff, and Stan Mazor to work with Busicom engineer Masatoshi Shima. In November of 1971, the world's first single-chip microprocessor, the Intel 4004, was released. The team created the chip which consisted of 2,300 P-MOS transistors in an area of about 3 by 4 millimeters.
The Intel 4004 executes about 100,000 instructions per second, has a 45 command instruction set, and performs basic addition and subtraction. It requires 15 VDC and a peculiar clock source to operate. Memory bus architecture is of the Harvard type but can be fooled into operating as von Neumann.
The 4004 was patented in 1974: U.S. Patent No. 3,821,715: Memory System for a Multi-Chip Digital Computer.3 Images of the patent may be viewed at this link.	Busicom created a high-end business calculator using the four-chip 400X set in 1971. Federico Faggin produced the prototype depicted in these three pictures.
	The Pioneer 10 spacecraft used the 4004 microprocessor. It was launched on March 2, 1972 and was the first spacecraft to enter the Asteroid Belt. By the way, Intel stands for Integrated Electronics and was founded in 1968 with the original name of M&N Electronics. Without confirmation, I believe the 'M' stands for Moore (Gordon) and the 'N' stands for Noyce (Robert). I believe this because Intel was created by Noyce and two colleagues from the Shockley group.2

World's First Microcomputer

The Intel 4004. It was supposed to be the brains of a calculator. Inste ad, it turned into a general-purpose microprocessor as powerful as ENIAC.

• a microcomputer is a computer that's based on a microprocessor
• world's first was the MCS-4 Microcomputer System
• 4 bit processor
• 45 instructions
• Decimal and Binary arithmetic modes
• 100000 instructions per sec.
• JSR but no stack (nesting up to 3 levels)
• 16 general purpose reg. (4bit)
• drives 4k bytes ROM (16 4001 DIPs)
• drives 1280 nibbles of RAM (16 4002 DIPs)
• p channel MOS

the MCS-4 computer used:

• the 4004 microprocessor;
• the 4001 ROM
• the 4003 shift register

A Brief Microprocessor History

• calculators (Busicom...computronic)
• prior use of ASICs, then 4004 introduced