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[marsgithu]

Hi there,

Firstly, thank you for open sourcing IBEX; it's truly impressive work. I have a quick question regarding the bus protocol used by the data bus and instruction bus of the IBEX core. Is this a standard bus protocol or was it developed in-house? If it's a standard protocol, could you please share its name and direct me to the relevant documentation?

Thank you in advance for your time and assistance!

My Environment

EDA tool and version:

Operating system:

Version of the Ibex source code:

[GregAC]

The protocol is documented here: https://ibex-core.readthedocs.io/en/latest/03_reference/load_store_unit.html#protocol

It is effectively custom, though it came to us from the PULP project and in turn that has gone to the OpenHW group who have produced the Open Bus Interface: https://github.com/openhwgroup/obi/blob/072d9173c1f2d79471d6f2a10eae59ee387d4c6f/OBI-v1.6.0.pdf

However last I checked our protocol isn't quite OBI compatible, in particular it's got rules about feedthroughs that we violate (The valid input from the data memory response is combinationally connected to the valid output from the data memory request)