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Jan 13, 2026 5:57 PM UTC
Solved

Understanding VALID/READY handshakes (AXI/AMBA)

Hi everyone! I’ve been diving into the AXI4 protocol for a small design exercise, and while I’m making progress, I’m still trying to build a solid intuition for the VALID/READY handshake, especially on the less 'visible' channels like the Write Response (B channel)...

I’ve spent quite a bit of time with the official specification, but there’s a difference between reading the rules and actually 'seeing' how the handshakes play out in a high-performance design. for those of you who work with ARM buses or SoC design professionally, what was the 'aha!' moment for you?

did you find it most heloful to strictly study the timing diagrams, or was it more about building small simulation testbenches and observing how the bus stalls when READY is de-asserted??? I’m trying to avoid getting overwhelmed by the sheer volume of the spec and instead focus on a practical, design-first understanding. Any advice on learning strategies or common pitfalls to watch out for would be incredibly helpful. Thanks!

 

Andrew Neil
Andrew NeilBest answer
Super User
Jan 14, 2026 10:41 AM UTC

This sounds like a question for ARM rather than ST:

https://community.arm.com/support-forums/f/architectures-and-processors-forum 

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.

2 replies

Andrew Neil
Andrew NeilBest answer
Super User
Jan 14, 2026 10:41 AM UTC

This sounds like a question for ARM rather than ST:

https://community.arm.com/support-forums/f/architectures-and-processors-forum 

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
Jan 15, 2026 12:12 PM UTC

Hey, thanks for this help. let me check the link and see if I need any help here.