K20 + eMMC/MMC + ESDHC

[sulley]

Hello all,

I'm hoping to pick your brains regarding MQX and the ESDHC driver.....

I'm working on a ATEX version of an existing product at the moment. It's a GSM RTU based on the K20. I am replacing a micro SDHC card and socket for a Micron MTFC4GLDDQ-4M eMMC device, basically a BGA with the same connections as an SD/MMC card. Hooking the device up to my PC in single bit mode works fine, fully functional. However, connecting it up to the K20, running MQX with the ESDHC driver, it doesn't want to play ball. The ESDHC driver should be compatible with the MMC protocol, however it reports ESDHC_CARD_UNKNOWN as the card type. I've tried both 4bit and 1bit interfaces with the same result, although it's worth mentioning that MMC interface starts up in 1bit mode regardless.

The eMMC device is designed to work with the MMCplus protocol, however this protocol is backwards compatible with the original MMC protocol. This information is of importance because I'm only connecting the device using the first data line and also the ESDHC driver doesn't mention MMCplus being supported.

I am still working with the software engineer on resolving this, but I thought it would be useful to ask if anyone has utilised the MMC functionality of the ESDHC driver? or even used an eMMC device with a K20 or similar?

Thanks for taking the time to read this,

Kind Regards,

Rob

[axelrichter]

Hello Rob,

are there any updates in using eMMC with MQX? We want to use an eMMC connected to a Vybrid VF6xx.

Best regards,

Axel Richter

[sw_bob]

Thanks, Rob.

Yeah, that's not the answer I was hoping to get.

I may try 4.1.1 from the USB stack example above.

What is strange is that eMMC part we have should behave exactly like an external SD card, but it doesn't.

Both regular and SDHC cards work with the same stack on the Tower system.

-Boris

[sw_bob]

Rob,

I am having an exact same issue with K64 HW. As a matter of fact, I am also using Micron eMMC part (very similar to yours).

Did you find a resolution to the issue you've mentioned above?

Thank you,

Boris

[sulley]

Hi Boris,

Our client is running MQX 3.?, Kan Li offered upgrading to 4.1 as a solution, however they were not keen on this. Some time was spent comparing the differences between the versions to no avail, in the end they wrote their own stack. Sorry, this probably does not come as good news to you!

For completeness and future reference, Boris is running MQX 4.1.

If you make any progress with another approach, keep us posted.

Good luck,

Rob

[Kan_Li]

Hi Rob,

I am not sure which revision of MQX that you are using, but I remember someone has told me the ESDHC driver in earlier MQX version has some issue but got fixed in ver 4.1, so if you are using any previous version, would you please switch to the latest and try again? Another info is that FSL USB stack ver 4.1.1 also implemented a USB SD card demo, maybe you can also try this to see if it makes any difference. You may get FSL USB stack ver 4.1.1 from USB Stack , and after installation , you may find that demo in the folder of "C:\Freescale\Freescale USB Stack v4.1.1\Source\Device\app\msd\cw10\kinetis_k20".

Hope that helps,

Have a great day,
Kan

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[pbanta]

I think there is still a problem with the ESDHC driver in MQX 4.1.

I'm trying to use a Kingston KE4CN2H5C with a K70.  The driver always fails when trying to determine the type of card.

As I study the code in sdcard_esdhc.c:_io_sdcard_esdhc_init() and esdhc.c:_esdhc_get_card_type() I can see that the init sequence doesn’t seem to follow Figure 26 in the JEDEC Standard No. 84-A44, page 41 or Figure 22 in 84-B45, page 32.  Those figures show the following sequence:  CMD0, CMD1, CMD2, CMD3.  The driver doesn’t send all of those commands in that order.  I can see from the source code that an attempt was made to support both SD and MMC devices.  However, the driver does not follow the diagram in the Freescale's SD/MMC Deep Dive from FTF2010 (WBNR_FTF10_NET_F0598_PDF.pdf, page 17).  In MQX 4.1, right after the driver sends CMD55 it checks the return code and if it’s greater than 0, then it returns a failure code.  CMD55 always times out so the return code is always greater than zero.

Looks like the MQX 4.1 ESDHC driver needs some work to better support eMMC devices.