Motorola 68012

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The Motorola MC68012 processor is a 16/32-bit microprocessor from the early 1980s. It is an 84-pin PGA[1] version of the Motorola MC68010. The memory space was extended to 2GB and an RMC[2] pin was added, in order to help the design of multiprocessor systems with virtual memory.[3][4] All other features of the MC68010 were preserved.

The expansion of the memory space caused an issue for any programs that used the high byte of an address to store data, a programming trick that was successful with those processors that only have a 24-bit address bus (68000 and 68010). A similar problem affected the 68020.

Notes and references[edit]

  1. ^ Motorola 68012 (MC68012) microprocessor family
  2. ^ Read-Modify-write Cycle indicator, same as used on the MC68020 for multiprocessing support
  3. ^ DatasheetArchive :: Datasheet and Specsheet for MC68012RC12
  4. ^ Avtar, Singh. 16-Bit and 32-Bit Microprocessors: Architecture, Software, and Interfacing Techniques. New Jersey. Englewood Cliffs. 1991