Isn’t that kind of a problem to have different versions/implementations of the > U54-MC out there but only one datasheet?
What you are seeing online is a manual for the standard U54MC product. It should be for the most recent release (20G1.07) but it is actually a bit outdated and that will soon be updated.
When customers create a new design they receive customized documentation specific to their implementation options. Microchip received custom documentation and they have incorporated that into the PolarFire documentation. Ultimately you should be looking for PolarFire specific documents to see what has been implemented in their device.
Like, there is no information to link a specific hardware (in my case, the
PolarFire SoC) to a specific implementation (and therefore a specific
datasheet) of the U54-MC ? (Microchip/Microsemi only mention “U54-MC”,
Our IP is rapidly evolving and many new features are being added with each release. RISC-V defines the mimpid (Implementation ID) CSR so you can identify what IP you are working with. SiFive defines the mimpid as follows:
If you read this on the PolarFire it should read 0x0 as it comes from our Pre-19.02 generator. If you see the E5 referenced by the Microchip documents that became our S5 product.
We don’t maintain legacy manuals online, but if you create an SCD account (at
https://scs.sifive.com/) you’ll then be able to download standard builds for any version of the product. The documents will be located in the sifive_coreip/docs folder. You select the version from the top right pull-down as shown:
Last year we made a big push to improve the documentation. So you’ll see noticeable differences in content with the recent releases.
(Side note : It might also explain why the behavior of the
branch predictor mode CSR appears to be the opposite of what
is described in the datasheet)
I’m not sure, but that would be a question for Microchip after consulting their documentation.