Source : Free On-Line Dictionary of Computing

MCP-1600
     
        A processor made by {Western Digital}, consisting of at least
        four separate {integrated circuit}s, including the control
        circuitry unit, the {ALU}, two or four {ROM} chips with
        {microcode}, and timing circuitry.
     
        The ALU chip contained twenty-six 8-bit {register}s and an
        8-bit {ALU}, while the control unit supervised the moving of
        data, memory access, and other control functions.  The {ROM}
        allowed the chip to function as either an 8- or 16-bit chip,
        with clever use of the 8-bit {ALU}.  Further, {microcode}
        allowed the addition of {floating-point} routines (40 + 8 bit
        format), simplifying programming (and possibly producing a
        floating-point coprocessor).
     
        Two standard {microcode} {ROM}s were available.  This
        flexibility was one reason it was also used to implement the
        {DEC} {LSI-11} processor as well as the {WD} {Pascal
        Microengine}.
     
        (1994-11-18)