Features

• Fully eRM compliant AHB eVC

• Compliant with entire AHB protocol

• Designed for ease of integration and ease of use

• Small memory footprint

• Straightforward scoreboard and functional coverage monitor hooks

Applications

• Full multi-master multi-slave AHB systems

• Single master AHB-lite systems

• Multi-Layer AHB systems

Overview

The figure above shows a typical multi-master multi-slave AHB system.  DUTs are verified with passive eVCs.  Active eVCs are also attached to the AHB and can fully drive and respond to bus transactions.  A single master AHB without an arbiter can also be implemented.

All AHB features are supported:

• Early Burst Termination

• Continue or Cancel on Error

• Configurable Data and Address Bus Width

• Configurable Endianess

                            Interface Diagram

Architectural Details

The itrx_ahb_evc is implemented with the standard eRM architecture.  A configurable number of master and slave agents can be instantiated.  Each agent can be operated in either active or passive mode.  A passive agent only contains a bus monitor and checkers.  It drives no signals but is attached to and monitors DUT ports.  An active agent also contains a monitor and checkers.  It additionally contains a BFM and a sequence driver.  This allows an active agent to drive the AHB.

In a multi-master AHB an arbiter will be present.  The AHB eVC has a passive arbiter agent that implements arbitration checkers.  An active arbiter is not necessary since pre-verified AHB arbiter HDL implementations are readily available.  Arbitration checkers fully implement split, early burst termination, and locking protocols.

An AHB master must rebuild a burst that has been terminated by the arbiter.  The AHB eVC has a configurable burst rebuild scheme allowing a user to complete a burst in a variety of ways.  Rebuilding with single or incrementing bursts is supported.  A user can extend a method to implement alternative schemes.

A unique and powerful method for controlling active slave agents has been implemented.  Instead of a sequence driver, the active slave agent uses an algorithmic method to control slave response behavior.  This greatly enhances the ability to have a slave agent model hardware accurately.

Hooks in both the master and slave agents make it easy to implement external scoreboards and functional coverage monitors.  Events are emitted at important AHB protocol boundaries, like the start and end of transfers and bursts.  Public data structures capture AHB transfers and bursts on these boundaries make the hookup of scoreboards and functional coverage straightforward.

The AHB eVC supports both little and PowerPC endianness (byte-invariant big endian).  A user can easily implement alternative endian schemes by extending a single data structure.

                            itrx_ahb_evc Architecture