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Knowledge Center

IEEE-ISTO 5001 (Nexus 5001) — embedded processor debug



IEEE-ISTO 5001-2012, The Nexus 5001 Forum Standard Embedded Processor Debug Interfaces is an open industry standard that provides a general-purpose interface for the software development and debug of embedded processors. The IEEE Nexus 5001 real-time trace standard was introduced to add some consistency into the trace process in 1998. Tool vendors needed a standard interface to focus on, so they were not building custom tools for every single processor implementation.

The Global Embedded Processor Debug Interface Standard Consortium formed to maintain the standard in April 1998 to define and develop an embedded processor debug interface standard for embedded control applications. The group chose the IEEE Industry Standards and Technology Organization (IEEE-ISTO) for its forum and services in support of The Nexus 5001 Forum Standard. After over 20 years of maintaining a successful industry standard, the members of Nexus 5001 Forum dissolved the organization on September 30, 2020, but the Nexus standard will remain open and available for future adoption on the Nexus 5001 Forum website.

Nexus uses an existing JTAG port for debug.

The standard includes:

  • Program trace
  • Data trace
  • Memory access
  • Memory substitution
  • Breakpoints and watchpoints
  • Ownership trace
  • Port replacement
  • Time stamps