CADRE: A low-power, low-EMI DSP architecture for digital mobile phones

Current mobile phone applications demand high performance from the DSP, and future generations are likely to require even greater throughput. However, it is important to balance these processing demands against the requiremen t of low power consumption for extended battery lifetime. A novel low-power digital signal processor (DSP) architecture CADRE (Configurable Asynchrono us DSP for Reduced Energy) addresses these requirements through a multi-lev el power reduction strategy. A parallel architecture and configurable compr essed instruction set meets the throughput requirements without excessive p rogram memory bandwidth, while a large register file reduces the cost of da ta accesses. Sign-magnitude representation is used for data, to reduce swit ching activity within the datapath. Asynchronous design gives fine-grained activity control without the complexities of clock gating, and gives low el ectromagnetic interference. Finally, the operational model of the target ap plication allows for a reduced interrupt structure, simplifying processor d esign by avoiding the need for exact exceptions.