Understanding Smart Sensors - Nomads.usp

Control Techniques 1677.7.2 Combined CISC, RISC, and DSPAn interesting demonstration of the value of both of CISC and RISC is providedin a communications control circuit is shown in Figure 7.11 [26]. This isa single-chip solution incorporating CISC, RISC, and DSP technology. CISCtechnology (68000-based) is used for the integrated multiprotocol processor.Three serial communications channels handle high-level data-link control(HDLC), asynchronous (UART), BYSYNC, and synchronous protocols. APersonal Computer Memory Card International Association (PCMCIA) blockprovides a direct interface to a PCMCIA bus (PC card). RISC is used for thecommunication processor. As a result, the ports operate independent of the68000-host processor and allow the 68000 to handle higher level control tasks[27]. DSP technology provides increased performance through the parallel(Harvard) architecture. That allows it to simultaneously fetch program, X-data,and Y-data memory. Because both cores use common memory, cost is reduced.Communications enginePCMCIA68K bus68K68K busPort B16550RISCCPSCC2SCC3SCC1DirectaccessIRQA.BSSISCI+DSPExternalbus I/FInternalROM and RAM56K bus** No external DSPmemory neededFigure 7.11 Block diagram of combined CISC, RISC, and DSP for data communications.