Intel 8008 - Definition and Overview

The Intel 8008 was an early microprocessor designed and manufactured by Intel, and introduced in April, 1972. It 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.

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 very large amount of external logic to support it. For example, the 14-bit address, which could access 16K bytes of memory, needed to be latched by some of this logic in an external Memory Address Register (MAR). It could access 8 input ports and 24 output ports.

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.

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.