Technical specifications

Technical specifications

* Maximum clock speed is 740 kHz
* 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:
o 12-bit addresses
o 8-bit instructions
o 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.