Clarification of memories accessed by uDMA core

[cst-aditya]

As per the details mentioned at https://docs.openhwgroup.org/projects/core-v-mcu/doc-src/high_level_architecture.html#micro-dma-subsystem , uDMA cannot access the non-interleaved memories . However, the RTL implementation at **** does not impose such a restriction.

s_l2_dest mentioned in the above snippet is hardocded to 0, which means l2_addr_o[31:24] is always set to 0x1C. Now, if we look at below table in https://docs.openhwgroup.org/projects/core-v-mcu/doc-src/mmap.html it says both interleaved and non-interleaved memory starts at 0x1c.

Please help to resolve this ambiguity.

[MikeOpenHWGroup]

Hi @cst-aditya, this is a good observation. You are right that the micro-DMA controller does nothing to prevent access to non-interleaved memory. I had though that the TCDM Interconnect blocked accesses from the uDMA subsystem to non-interleaved memories. However, looking at the RTL, it seems that there is no such restriction.

So we should either:

1. Modify the RTL to introduce this restriction, or
2. Modify the User Manual to remove the statement: Note that the uDMA cannot access the non-interleaved memories or the boot ROM. from the document.

Let's discuss at our next bi-weekly meeting.

[cst-aditya]

Hi Mike, Thank you for the response! Yes, let's strategize this during the next bi-weekly meeting. Regards, Aditya

…

On Mon, Jul 21, 2025 at 8:59 PM Mike Thompson ***@***.***> wrote: *MikeOpenHWGroup* left a comment (openhwgroup/core-v-mcu#343) <#343 (comment)> Hi @cst-aditya <https://github.com/cst-aditya>, this is a good observation. You are right that the micro-DMA controller does nothing to prevent access to non-interleaved memory. I had though that the TCDM Interconnect blocked accesses from the uDMA subsystem to non-interleaved memories. However, looking at the RTL, it seems that there is no such restriction. So we should either: 1. Modify the RTL to introduce this restriction, or 2. Modify the User Manual to remove the statement: Note that the uDMA cannot access the non-interleaved memories or the boot ROM. from the document. Let's discuss at our next bi-weekly meeting. — Reply to this email directly, view it on GitHub <#343 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AMGHJ5UKCOLDGAI4XYA3MGL3JUBMPAVCNFSM6AAAAACBENOGFWVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTAOJXGI2DSNRSGQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

-- Thanks & Regards, Aditya Tiwari