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The MCP-1600 was a multi-chip microprocessor made by Western Digital in the late 1970s through the early 1980s.[1][2] Used in the Pascal MicroEngine, the original Alpha Microsystems AM-100, and the DEC LSI-11 microcomputer, a cost-reduced and compact implementation of the DEC PDP-11.

There were three types of chips in the chip-set:

  • CP1611 RALU - Register ALU chip
  • CP1621 CON - Control chip
  • CP1631 MICROM - Mask-programmed microcode ROM chip (512 – 22 bit words)

The chips used a 3.3MHz four phase clock and four power supply voltages (+5V, +12V, -12V, and -5V). Internally the MCP-1600 was a (relatively fast) 8-bit processor that could be micro-programmed to emulate a 16-bit CPU. Up to four MICROMs were supported, but usually two or three could hold the needed microprogram for a processor.

A clone of the CP1611 was manufactured in the Soviet Union under the designation K581IK1 (Russian: КР581ИК1).[3] The Soviet 581 series included other members of the MCP-1600 family as well.[4]


  1. ^ "Western Digital adds MCP-1600 Micro". Computerworld. 26 November 1975.
  2. ^ "Western Digital 1600". AntiqueTech. Retrieved 5 January 2017.
  3. ^ "Soviet microprocessors, microcontrollers, FPU chips and their western analogs". CPU-world. Retrieved 24 March 2016.
  4. ^ Козак, Виктор Романович (24 May 2014). "Номенклатура интегральных микросхем — Микропроцессоры: серии 580 - 589" [Nomenclature of integrated circuits — Microprocessors: Series 580 - 589] (in Russian). Retrieved 24 March 2016.