Medical Device Link .

Both reduced-instruction-set computer (RISC) microcontrollers (MCUs) and digital signal processors (DSPs) have traditionally served in media-rich embedded applications such as medical electronics. They are not used interchangeably; rather, they work in concert. MCU architectures are well suited for efficient asynchronous system control code execution while the bread and butter of DSP architectures is synchronous, constant-rate data flow (for example, filtering and transform operations). Because both function sets are necessary in today's media-processing applications, engineers often use separate MCU and DSP chips. This combination constitutes a good processing engine for a wide variety of multimedia applications, but it entails the added complexity of multiprocessing design, multiple development tool sets, and heterogeneous architectures to learn and to debug. Chip vendors have tried to alleviate these problems with several different solutions. Various MCU makers have integrated some signal- processing functionality in their devices, such as instruction-set extensions and multiply-accumulate (MAC) units, but these efforts often lack the essential architectural basis required for advanced signal-processing applications. Similarly, DSP manufacturers have incorporated limited MCU functionality into their processors, but with inevitable compromises in the system control domain. Another option has emerged recently, however—the embedded media processor (EMP). This processor presents both MCU and DSP functionality in a unified architecture that allows flexible partitioning between control and signal-processing requirements. As the application may demand, the EMP can act entirely as an MCU