The 8-bit processors

8008

  • Introduced April 1, 1972
  • Clock rate 500 kHz (8008–1: 800 kHz)
  • 0.05 MIPS
  • Bus Width 8 bits (multiplexed address/data due to limited pins)
  • Enhancement load PMOS logic
  • Number of Transistors 3,500 at 10 µm
  • Addressable memory 16 KB
  • Typical in early 8 bit microcomputers, dumb terminals, general calculators, bottling machines
  • Developed in tandem with 4004
  • Originally intended for use in the Datapoint 2200 microcomputer
  • Key volume deployment in Texas Instruments 742 microcomputer in >3,000 Ford dealerships

8080

  • Introduced April 1, 1974
  • Clock rate 2 MHz
  • 0.64 MIPS
  • Bus Width 8 bits data, 16 bits address
  • Enhancement load NMOS logic
  • Number of Transistors 6,000
  • Assembly language downwards compatible with 8008.
  • Addressable memory 64 KB
  • Up to 10X the performance of the 8008
  • Used in the Altair 8800, Traffic light controller, cruise missile
  • Required six support chips versus 20 for the 8008

8085

  • Introduced March 1976
  • Clock rate 3 MHz
  • 0.37 MIPS
  • Bus Width 8 bits data, 16 bits address
  • Depletion load NMOS logic
  • Number of Transistors 6,500 at 3 µm
  • Binary compatible downwards with the 8080.
  • Used in Toledo scales. Also was used as a computer peripheral controller – modems, harddisks,printers, etc...
  • CMOS 80C85 in Mars Sojourner, Radio Shack Model 100 portable.
  • High level of integration, operating for the first time on a single 5 volt power supply, from 12 volts previously. Also featured serial I/O,3 maskable interrupts,1 Non-maskable interrupt,1 externally expandable interrupt w/[8259],status,DMA.

MCS-85 Family:

Intel 8085.

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