RetroBBS - comp.arch.embedded - Re: eMMC CSD Register ECC field

eMMC CSD Register ECC field

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From: buzz_mccool@yahoo.com (Buzz McCool)
Newsgroups: comp.arch.embedded
Subject: eMMC CSD Register ECC field
Date: Tue, 12 Apr 2022 17:54:16 -0700
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by: Buzz McCool - Wed, 13 Apr 2022 00:54 UTC

Anyone here knowledgeable about eMMC memory?

I have a high reliability application where there is concern about
memory corruption. What would happen if I changed the ECC field in the
eMMC's Card Specific Data (CSD) register from the default no ECC to the
optional BCH(542,512) encoding? Would I still be able to write/read new
values to the eMMC normally with the eMMC internally protecting the
contents with BCH ECC at the cost of reduced memory capacity, or would a
special driver on the host be needed to encode/decode ECC reads/writes?

I've asked around and haven't found a definitive answer so far. Let me
know if you can help ... Buzz

Re: eMMC CSD Register ECC field

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From: sp4mtr4p.boudewijn@indes.com (Boudewijn Dijkstra)
Newsgroups: comp.arch.embedded
Subject: Re: eMMC CSD Register ECC field
Date: Thu, 9 Jun 2022 16:06:40 +0200
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by: Boudewijn Dijkstra - Thu, 9 Jun 2022 14:06 UTC

Buzz McCool schreef:
> Anyone here knowledgeable about eMMC memory?
>
> I have a high reliability application where there is concern about
> memory corruption. What would happen if I changed the ECC field in the
> eMMC's Card Specific Data (CSD) register from the default no ECC to the
> optional BCH(542,512) encoding? Would I still be able to write/read new
> values to the eMMC normally with the eMMC internally protecting the
> contents with BCH ECC at the cost of reduced memory capacity, or would a
> special driver on the host be needed to encode/decode ECC reads/writes?
>
> I've asked around and haven't found a definitive answer so far. Let me
> know if you can help ... Buzz

Asked around? Why not consult the standard? From there I gather that
eMMC devices may implement internal ECC (that is why the DEVICE_ECC_
FAILED status exists) and that the "ECC" configuration field may be used
for external ECC. If nonzero, your driver should handle the ECC
encoding/decoding.

--
(remove the obvious prefix to reply directly)

An adequate bootstrap is a contradiction in terms.

devel / comp.arch.embedded / Re: eMMC CSD Register ECC field

Subject	Author
eMMC CSD Register ECC field	Buzz McCool
Re: eMMC CSD Register ECC field	Boudewijn Dijkstra