Intel 8008
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,
| Intel 8008 Central processing unit |
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 An Intel 8008 Microprocessor |
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| Produced: | mid 1972 |
| Manufacturer: | Intel |
| CPU Speeds: | 0.5 Mhz to 0.8 Mhz |
| Instruction Set: | pre x86 |
| Socket: | 18 pin DIP |
The Intel 8008 was an early microprocessor designed and manufactured by Intel and introduced in April, 1972. The 8008, originally codenamed 1201, was originally commissioned by Computer Terminal Corporation for use in its Datapoint 2200 programmable terminal, but because the chip was delivered late and did not meet CTC's performance goals, the chip was not used in the 2200. An agreement between Intel and CTC permitted Intel to market the chip to other customers.
Initial versions of the 8008 ran at 0.5 MHz, later increased to 0.8 MHz. While a little slower in terms of instructions per second than the 4-bit Intel 4004 and Intel 4040, the fact that the 8008 processed data eight bits at a time and could access significantly more RAM actually gave it 3 to 4 times the true processing power of the 4-bit chips.
The instruction set of the 8008 and subsequent Intel CISC CPUs were heavily based on CTC's design.
The chip (limited by its 18 pin DIP packaging) had a single 8-bit bus and required a significant amount of external support logic. For example, the 14-bit address, which could access 16 kibibytes of memory, needed to be latched by some of this logic into an external Memory Address Register (MAR). The 8008 could access 8 input ports and 24 output ports.
For controller and CRT terminal use this was an acceptable design, but it was too difficult to use for most other tasks. A few early computer designs were based on it, but most would use the later and greatly improved Intel 8080 instead.
The 8008 family is also referred to as the MCS-8.
[edit] Designers
- CTC (Instruction set and architecture): Victor Poor and Harry Pyle.
- Intel (Implementation in silicon):
- Marcian "Ted" Hoff and Stan Mazor proposed a single-chip implementation of the CTC architecture, using RAM register memory rather than shift register memory, and also added a few instructions and interrupt facility
- Federico Faggin become leader of the project from January 1971, after it had been suspended for about 7 months, until its successful completion in April 1972
- Hal Feeney project engineer did the detailed logic design, circuit design, and physical layout under Faggin's supervision, employing the same design methodology Faggin originally developed for the Intel 4004 microprocessor
[edit] External links
- A Brief History of Microprocessors
- MCS-8 User Manual with 8008 data sheet (1972)
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