AMBA 3 Overview

The Arm AMBA 3 specification defines a set of four interface protocols that, between them, cover the on-chip data traffic requirements from data intensive processing components requiring high data throughput, low bandwidth communication requiring low gate count and power and on-chip test and debug access.

  • AMBA 3 AXI

    Supporting highly effective data traffic throughput through five unidirectional channels

    AXI Specification
  • AMBA 3 AHB

    Enabling highly efficient interconnect between simple peripherals in a single frequency subsystem

    AHB Specification
  • AMBA 3 APB

    Supporting low bandwidth transactions for accessing peripherals

     

    APB Specification
  • AMBA 3 ATB

    A data agnostic interface for trace data that provides visibility for debug purposes

    ATB Specification

AMBA 3 Descriptions

AMBA 3 AXI Interface

The AMBA 3 AXI interface specification provides the characteristics to support highly effective data traffic throughput. The five unidirectional channels with flexible relative timing between them, and multiple outstanding transactions with out-of-order data capability enable:

  • Pipelined interconnect for high speed operation
  • Efficient bridging between frequencies for power management
  • Simultaneous read and write transactions
  • Efficient support of high initial latency peripherals

AMBA 3 AHB Interface

The AMBA 3 AHB interface specification enables highly efficient interconnect between simpler peripherals in a single frequency subsystem where the performance of AMBA 3 AXI is not required. Its fixed pipelined structure and unidirectional channels enable compatibility with peripherals developed for the AMBA 2 AHB-Lite specification.

AMBA 3 APB Interface

The AMBA 3 APB interface specification supports the low bandwidth transactions necessary to access configuration registers in peripherals and data traffic through low bandwidth peripherals. The highly compact and low power interface isolates this data traffic from the high performance AMBA 3 AHB and AMBA 3 AXI interconnects. The AMBA 3 APB interface is fully backwards compatible with the AMBA 2 APB interface allowing existing APB peripherals to be used.

AMBA 3 ATB Interface

The AMBA 3 ATB interface specification adds a data agnostic interface for trace data in a trace system to the AMBA specification. The trace components and bus sit in parallel with the peripherals and interconnect and provide visibility for debug purposes.