Embedded processor applications for SONET telecommunication systems

In order to meet the increased bandwidth requirements of today's telecommunications systems, several designers are using Synchronous Optical NETwork (SONET) protocol to transfer voice and data over fiber optic lines. This solution provides for clear and reliable transport of information between users. At the center of these systems are embedded processors which allow for access to nearly all SONET network information. Additionally, some processors incorporate communications controllers for transfer of SONET Data Communication Channel (DCC) information as well as a UART for data transfers between the host and target systems. Contained on board with the processor are several firmware routines stored in memory that are executed by the processor when instructed by the host system. Performance monitoring, error detection, and alarm conditions are all reported through embedded processor access. This paper gives a brief SONET overview and discusses embedded processor system components, embedded processor functions, firmware development, and design considerations for embedded SONET system applications. Along with describing these areas, a case study of a SONET evaluation system using a Motorola MC68302 embedded processor is provided.