Avalon® Interface Specifications

ID 683091
Date 9/26/2022
Document Table of Contents
Give Feedback

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 credit 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, sources can start data transfers only if they have credits available. Similarly, sinks can accept data only if they have outstanding credits.
  • Symbol—a symbol is the smallest unit of data as defined for the interface. One or more symbols make up the single unit of data transferred in a clock cycle. The default symbol size is 8 bits.
  • 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.