eMMC compatability question

Frank Walzer

My aerospace customer is designing an AM335x board with eMMC on MMC0 (no other pin-mux option). They claim to be aware about the limitations of that interface but would like to know if they have to expect issues when using an 8GB device (here MTFC8GLDDQ-4M IT). They say the device is JEDEC 4.41 compatible. Plan is to have boot partiition at start of device memory range.

Do we expect any issues with this? Or would this require a real test? (OS will be Linux here)

Thanks,

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Frank,

I don't know if this has ever been tested. A relatively simple/cheap way to test this would be to make a PCB that fits into the SD card socket, solder the eMMC on it and test on one of the EVMs.

0 Frank Walzer over 11 years ago in reply to Biser Gatchev-XID

TI__Mastermind 44306 points

Bieser,

great idea but I don't have the time to do that. Could you please request a comment from an MMC expert in the BU?

thanks,

0 Biser Gatchev-XID over 11 years ago in reply to Frank Walzer

TI__Guru**** 393215 points

I will do that.

0 Frank Walzer over 11 years ago in reply to Biser Gatchev-XID

TI__Mastermind 44306 points

Hi Biser,

any news here?

regards,

0 Biser Gatchev-XID over 11 years ago in reply to Frank Walzer

TI__Guru**** 393215 points

Nothing so far. I asked again today.

0 Jeff Culverhouse over 11 years ago

TI__Genius 9190 points

Hello Frank,

If they are using 8GB eMMC for boot they need to use MMC1 as stated in the TRM init section. This is because of the way some eMMC devices do not strictly adhere to the 4.41 spec for the initialization. If the device they are using does not strictly adhere to section 7.4.2 of the 4.41 spec then there can be issues. We have seen many memories not adhere to this so I would strongly advise against using MMC0. If they really need to use MMC0 then they need to ensure that the eMMC sends the correct fixed pattern response for CMD1, ARG = 0 of 0x40FF808 on the 8GB device, if not, it will fail to boot.

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eMMC compatability question