ARM AMBA Bus

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Last Updated: Thursday, 22 October 2026 01:32

Published: Wednesday, 01 April 2020 23:05

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ARM microcontrollers use proprietery bus i/f both to communicate internally as well as externally. This proprietery bus i/f is based on AMBA spec. The Advanced Microcontroller Bus Architecture (AMBA) specification defines an onchip communications standard for designing high-performance embedded microcontrollers.

Many distinct buses are defined within the AMBA specification. Some of these are:
• the Advanced High-performance Bus (AHB)
• the Advanced Peripheral Bus (APB).
* AXI Bus

AMBA based ARM microcontrollers use AHB as the cpu bus, which connects to high speed devices as memory, and also connected to to a bridge which is connected to a lower b/w APB bus, where most of peripheral devices are connected.

AHB:

AHB is the main bus connecting processor to memory and other high speed devices. This is the bus you see coming out of cortex processor to connect to other devices.

AHB Top level Diagram => AHB_top_level_diagram.jpg

AXI Bus (Advanced Extensible Interface):

Good link for basics here: https://www.vlsiverification.net/amba/axi/index.html

AXI Top level Diagram => AXI_top_level_diagram.jpg