Avalon® Interface Specifications

ID 683091
Date 1/24/2022

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Document Table of Contents

6.1. Terms and Concepts

The Avalon® Streaming Credit interface protocol defines the following terms and concepts:
  • Avalon® Streaming Credit System— An Avalon® Streaming Credit system contains one or more Avalon® Streaming Credit connections that transfer data from a source interface to a sink interface.
  • Avalon® Streaming Credit Components— A typical system using Avalon® Streaming interfaces combines multiple functional modules, called components. The system designer configures the components and connects them together to implement a system.
  • Source and Sink Interfaces and Connections—When two components are connected, credits flow from the sink to the source; and the data flows from the source interface to the sink interface. The combination of a source interface connected to a sink interface is referred to as a connection.
  • Transfers— A transfer results in data and control propagation from a source interface to a sink interface. For data interfaces, source can start data transfer only if it has credits available. Similarly, sink can accept data only if it has outstanding credits.
  • Symbol—A symbol is the smallest unit of data. One or more symbols make up the single unit of data transferred in a cycle.
  • Beat—A beat is a single cycle transfer between a source and sink interface made up of one or more symbols.
  • Packet—A packet is an aggregation of data and control signals that is transmitted together. A packet may contain a header to help routers and other network devices direct the packet to the correct destination. The packet format is defined by the application, not this specification. Avalon® Streaming packets can be variable in length and can be interleaved across a connection. With an Avalon® Streaming Credit interface, the use of packets is optional.