ADSP-2102

The ADSP-21020 is the first member of Analog Devices' family of single-chip IEEE floating-point processors optimized for digital signal processing applications. Its architecture is similar to that of Analog Devices' ADSP-2100 family of fixed-point DSP processors.

Fabricated in a high-speed, low-power CMOS process, the ADSP-21020 has a 30 ns instruction cycle time. With a highperformance on-chip instruction cache, the ADSP-21020 can execute every instruction in a single cycle. The ADSP-21020 features:

• Independent Parallel Computation Units

The arithmetic/logic unit (ALU), multiplier and shifter perform single-cycle instructions. The units are architecturally arranged in parallel, maximizing computational throughput. A single multifunction instruction executes parallel ALU andmultiplier operations. These computation units support IEEE 32-bit single-precision floating-point, extended precision 40-bit floating-point, and 32-bit fixed-point data formats.

• Data Register File

A general-purpose data register file is used for transferring data between the computation units and the data buses, and for storing intermediate results. This 10-port (16-register) register file, combined with the ADSP-21020's Harvard architecture, allows unconstrained data flow between computation units and off-chip memory.

• Single-Cycle Fetch of Instruction and Two Operands The ADSP-21020 uses a modified Harvard architecture in which data memory stores data and program memory stores both instructions and data. Because of its separate program and data memory buses and on-chip instruction cache, the processor can simultaneously fetch an operand from data memory, an operand from program memory, and an instruction from the cache, all in a single cycle.

• Memory Interface

Addressing of external memory devices by the ADSP-21020 is facilitated by on-chip decoding of high-order address lines to generate memory bank select signals. Separate control lines are also generated for simplified addressing of page-mode DRAM.

The ADSP-21020 provides programmable memory wait states, and external memory acknowledge controls allow interfacing to peripheral devices with variable access times.