A modular method for designing custom signal processing integrated circuits

A microprocessor architecture has been developed which enables a customized digital signal processor (DSP) to be assembled from a library of predefined modules (silicon macro-cells). The processing modules when assembled form a MOVE data-path structure. A MOVE data-path structure is also used for the control section, and the two combined form a regular and compact silicon layout. The modules consist of control, RAM, ROM, ALU, shift, logic, I/O, multipliers, and custom designed circuits for special functions. The modular approach evolved from attempts to put into silicon the Adaptive Differential Pulse Code Modulation (ADPCM) speech coding algorithm, and this has been the first application. One processor is used for the encoder, another for the decoder, and both are small enough to be placed inside a 16 pin dual-in-line package. Fabricated in 2.5 micron twin-tub CMOS, each processor is approximately 2mm by 6mm and contains 10,000 devices.