VF61 - memory used by CE 6 on A5 core

Technical Support
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1

Only to be 100% sure:
does CE 6 on A5 core on Vf61 uses DDR only?

Is it safe to use OCRAM, TCML and TCMU for M4 core without any additional setting needed?

2

OCRAM is used for suspend-resume (keeping data used to resume the system and code that runs in that phase), TCML and TCMU are not used by the A5.

3

OCRAM used is from 0x3F000000 to 0x3F003FFF.

4

@valter.tx only to be 100% sure:
I upgraded Toradex CE 6 to version 1.6b4, and I don’t know if this changes something.

A5 core uses only a little portion of OCRAM (0x3F000000 to 0x3F003FFF - this means 0x4000 bytes).

Can you confirm, please?

Moreover, RPMSG communication both on A5 and M4 sides uses only RX and TX buffers in the OCRAM at addresses 0x3F070000 and 0x3F074000.
I know I can reconfigure them in M4 and A5 accordingly, but I didn’t modified the default settings.

Can you confirm this, please?

But after my deep investigation for this issue it seems that something (maybe RPMSG communication) unexpectedly writes into the OCRAM from 0x3F060000 to 0x3F06FFFF too.

6

This answer required some time but, after a deeper investigation on this topic we have:

A5 uses two regions of OCRAM

  • from 0x3F000000 to 0x3F003FFF for suspend and resume
  • from 0x3f060000 to 0x3f063FFF for rpmsg communication (at least with Toradex CE Libraries 2.3-20181011)