IEC 61691-7:2025

Overview

IEC 61691-7:2025 - Behavioural languages, Part 7: SystemC® Language Reference Manual (also published as IEEE Std 1666) provides a precise, normative definition of the SystemC C++ class library including Transaction Level Modeling (TLM). The standard specifies the language-level API, elaboration and simulation semantics, core classes (for example sc_module, process control, and ports), and a TLM library so that independent SystemC implementations and tools can be developed from this specification alone. It is published as a double-logo IEC–IEEE standard; changes since the previous edition are documented in Annex D.

Key topics and requirements

• Language and library definition: normative class and header specifications for SystemC/TLM as a C++ class library.
• Elaboration and simulation semantics: detailed rules for instantiation, scheduling, initialization, callbacks (e.g., before_end_of_elaboration, start_of_simulation, end_of_simulation) and time management.
• Core classes and APIs: definitions and constraints for key classes such as sc_module, sc_module_name, sc_sensitive, sc_spawn, sc_process_handle and related process control members.
• Scheduler and runtime functions: standardized functions including sc_start, sc_main, sc_pause, sc_stop, sc_time_stamp, delta-cycle and activity detection APIs.
• TLM support: a TLM library specified for transaction-level communication and modeling of system-level behavior.
• Conformance and implementation guidance: normative conventions, terminology, and compatibility with the C++ standard; guidance for implementers and tool vendors (note: not intended as an introductory user guide).

Applications

• System-level and hardware/software co-design using SystemC and TLM.
• Rapid architectural exploration, performance modeling and virtual platform creation.
• Development of interoperable simulators, EDA tools, and verification environments.
• Academic research and teaching in system modeling and transaction-level simulation.
• Standardized baseline for companies requiring cross-tool SystemC model portability.

Who should use this standard

• EDA tool and simulator developers implementing SystemC/TLM runtimes.
• System architects and hardware/software designers doing system-level modeling.
• Verification engineers building TLM-based testbenches and virtual prototypes.
• Standards teams and integrators seeking reproducible semantics for SystemC models.

Related standards

• IEEE Std 1666 (equivalent publication)
• Relevant C++ language standards (for interoperability and implementation constraints)

Keywords: IEC 61691-7:2025, SystemC, TLM, SystemC Language Reference Manual, IEEE Std 1666, sc_module, sc_start, transaction-level modeling, hardware/software co-design.