Transaction-Level Modeling 


ZeBu allows you to simulate and debug a design at very high clock frequencies. Transaction-Level Modeling provides checkers, monitors and data generators with the throughput your DUT requires.


  • Speed: ZeBu transactors offer the highest performance on the market. Transaction-level performance is easily characterized by two parameters: bandwidth and latency. ZeBu can stream data to and from a design at up to 800 Mbit/s. Latency directly dictates how many messages can be processed by a testbench. ZeBu reaches up to 500,000 round-trip messages per second.
  • Reuse: ZeBu separates the implementation of the protocol(s) from the generation of test scenarios, such that transactors are reusable, and testbenches can be assembled easily from building blocks.
  • Easy of use: You can either buy off-the-shelf transactors for most common protocols, or design your own if you have a unique interface/application. The main part of a custom transactor is the Bus Functional Model (BFM) or Finite State Machine (FSM) for your interface, which can be written in standard Verilog or VHDL RTL, or in behavioral SystemVerilog using ZEMI-3, Synopsys' transactor compiler. Most likely, you already have a similar piece of code that can be easily converted to act as a transactor.

Various languages can be used for the transaction-based testbench:

  • C/C++/SystemC testbench: ZeBu transactors are adapted from the SCE-MI standard and follow a simplified/optimized API so that you can be up and running with only a few lines of code. An API fully-compliant with SCE-MI is also available if compatibility across emulation platforms is more important than performance.
  • SystemVerilog testbench: ZeBu transactors can be integrated with SystemVerilog testbenches using the standard ZeBu API, the SystemVerilog DPI, a SystemVerilog class, and the Verification Methodology Manual (VMM) Hardware Abstraction Layer (HAL), also from Synopsys.

The ZEMI-3 Transactor Compiler from Synopsys also simplifies the creation of transactor FSMs, and has the added benefits of:

  • Supporting behavioral constructs, such as implicit state machines, wait states and mixed clock edges
  • Automatic implementation of the transactor communication infrastructure
  • Performance optimization via streaming, prefetching

See Also

Product: Validation IP

Product: ZEMI-3 Transactor Compiler

Performance and Accuracy

The concept of transactors has been used in verification for a long time. A layered testbench cleanly separates the high-level protocol functions (for instance reading and writing on a AHB bus) from the low-level implementation (toggling the control and data signals of the AHB bus). ZeBu takes the concept one step further by off-loading the low-level transaction encoding and decoding into dedicated, customizable hardware. That accomplishes two unique goals: cycle accuracy, high performance — on par with traditional in-circuit emulation (with live circuits).

transaction level modeling

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