topic Re: Confusion regarding Minimum OCRAM Size in i.MX RT Crossover MCUs

Confusion regarding Minimum OCRAM Size

gh78731 — Fri, 07 May 2021 19:56:05 GMT

Regarding AN12077 : Using the i.MX RT FlexRAM (Rev 3, 01/2021)
https://www.nxp.com/docs/en/application-note/AN12077.pdf

and

i.MX RT Knowledge Base : Reallocating the FlexRAM
https://community.nxp.com/t5/i-MX-RT-Knowledge-Base/Reallocating-the-FlexRAM/ta-p/1117649

AN12077 on page 4, says "The minimum configuration of OCRAM is 64 KB (see Table 1)."

Then it proceeds to offer configurations 1, 3, 4 and 6 that violate this rule, with only 32 kB.

Does this mean that configurations 1,3, 4, and 6 should not be used, and should probably be grayed out, or removed from the table?

Then in the Knowledgebase article "Reallocating the FlexRAM", on approximately lines 17 and 18, says
"One thing that's important to mention is that the ROM in all the RT10xx parts uses 32KB of OCRAM, hence you should keep at least 32KB of OCRAM when reallocating the FlexRAM..."

This would suggest that all entries in table 1 in AN12077 are valid, and the Note under section 2.1.1.1 is in error.

Which one is correct?

I would like a clarification before I start reallocating SRAM, because the allocation using the eFuses is permanent, and can not be reversed.

Thanks,
--- Graham

Re: Confusion regarding Minimum OCRAM Size

victorjimenez — Wed, 12 May 2021 22:15:26 GMT

Hello Graham,

I'm checking this internally, I will give you an update as soon as possible. Thanks for your patience.

Regards,
Victor

Re: Confusion regarding Minimum OCRAM Size

victorjimenez — Thu, 13 May 2021 17:34:47 GMT

Hello Graham,

Thanks for catching this! I already fixed the community document. Regarding the amount of OCRAM, please be aware of the following part of the note.

For the RT1010, the amount of OCRAM needed is 32KB. For all the other RT10xx families, you need 64KB.

Regards,
Victor

Re: Confusion regarding Minimum OCRAM Size

gh78731 — Thu, 13 May 2021 21:08:10 GMT

Victor:

OK, that clarifies things.

Thanks for getting the documents fixed.

--- Graham