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AMBA Introduction

The Arm AMBA (Advanced Microcontroller Bus Architecture) protocols are an open standard, on-chip interconnect specification for the connection and management of functional blocks in a System-on-Chip (SoC). It facilitates right-first-time development of multi-processor designs with large numbers of controllers and peripherals.



  • AMBA 4 ACE - AXI Coherency Extensions - Used in big.LITTLE  systems for smartphones, tablets, etc.
  • AMBA 4 AXI4 - AXI4 is an update to AXI3 to enhance the performance and utilization of the interconnect when used by multiple masters.
  • AMBA 4 LPI – Low Power Interfaces – Used for power and clock management of SoC components.


  • AMBA 3 AXI - Advanced eXtensible Interface - The most widespread AMBA interface. Connectivity up to 100's of Masters and Slaves in complex SoCs.
  • AMBA3 AHB-Lite specification  -  Advanced High-Performance Bus - The main system bus in microcontroller usage.
  • AMBA 3 APB - Advanced Peripheral Bus - Minimal gate count for peripherals.
  • AMBA 3 ATB - Advanced Trace Bus - For moving trace data around the chip, see CoreSight Debug and Trace.

Features of AMBA Interfaces

IP reuse is essential in reducing SoC development costs and timescales. AMBA specifications provide interface standards that enables IP re-use if the following essential requirements are met:


IP reuse requires a common standard while supporting a wide variety of SoCs with different power, performance and area requirements. With its ACE, AXI, AHB and APB interface protocols, AMBA 4 has the flexibility to match every requirement. With AMBA 5 CHI interface Arm extends performance and scalability to many coherent processors.

Wide Adoption

There is a large amount of IP available in the industry today. AMBA caters for this IP and engineers across the globe have accepted it as a standard and use it daily. It is the most widely adopted industry standard for on-chip connectivity for IP products varying from; Memory Controllers, Interconnects, Trace solutions, GPUs, CPUs


It is a standard interface specification that ensures compatibility between IP components from different design teams or vendors. The AMBA specifications are available as both a written specification as well as a set of assertions that unambiguously define the interface protocol, thus ensuring this level of compatibility.


The wide adoption of AMBA specifications throughout the semiconductor industry has driven a comprehensive market in third party IP products and tools to support the development of AMBA based systems. The availability of SystemVerilog assertions for AMBA promote this industry wide participation.