i.MX6UL eMMC and micro SD same time

[zoltanszabo]

Hello,

We are designing a custom hardware for our customer, with i.mx6ul. We are not so familiar with it, so we started to build based on available  EVK schematics.

The hardware need to have emmc and micro SD at same time, but on EVK schematic this are an OR option, and are connected to the i.mx6ul NAND port, I mean share same data lines, as marked with green on attached Untitled8.png. Of course this should be no problem if just one of them are installed, but we need both at same time. 

The i.mx6ul has a dedicated SD port too, but on the EVK next to that is mentioned # SD CARD FULL SIZE  what makes us confused, as theoretically also micro SD could be connected there, or may be there is some reason that we dont know, for full size SD.

Actually we didnt fount any reference schematic which use emmc and micro SD at same time. We ques that emmc should be connected to the NAND port, while the micro SD to the SD port, but we are not sure about.

Could someone confirm, or better give as link to a schematic that use emmc and micro SD at same time ?

Thank You in advance !

Zoltan

[art]

Actually, the i.MX6UL EVK board implements two SD ports. The SD2 port is routed on the i.MX6UL CPU SODIMM board (please refer to the Sheet 6 of the SPF-28617 schematic) and has the options of installing either a microSD socket (J301, default) or eMMC chip (U301, can be installed in place of J301 after J301 removal). The SD1 port (refer to the Sheet 7 of the SPF-28617 schematic) is routed through the SODIMM board interconnector to the i.MX6UL EVK Base Board (refer to the SPF-28616 schematic, its Sheet 16 shows the board interconnector) that has the full-size SD/SDIO socket installed (refer to Sheet 12).

So, for your case, you can use the SD2 port to connect eMMC device (follow the corresponding option on the SPF-28617 schematic) and the SD1 port to connect a microSD slot (follow both SPF-28617 and SPF-28616 schematics).

Have a great day,
Artur

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[zoltanszabo]

Dear Artur,

Updated the sch with all EMMC signal connections. The target emmc for our application is from WD, which has RCLK (Data Strobe) and QRDY signals.

I think we QRDY could be left unconnected as it is just an optional pin.

But RCLK should be connected somewhere. Of course can be connected to any IO, but could You recommend please any connection to work well with existing linux driver ?

The micro SD is connected to SD1, no issues fount there.

Thank You !

Zoltan

[art]

According to the eMMC standard by JEDEC, this Returned Clock/Data Strobe signal is only applicable in the eMMC HS400 transfer mode, which is not supported by the i.MX6UL processor. So, seems that this signal can be just left unconnected as well.

Best Regards,
Artur

[zoltanszabo]

Thank You Artur !

Yes, I was thinking same, as You described, but as Im not familiar with i.mx6UL, mainly Im just the HW (PCB) designer of this project, and had some doubt, but now get confirmed, so can go on with design.

Will finish the schematic soon, that will post it here if you would be so kind just to have a quick lool, as after few protos and testing our customer has huge volumes in mind, so we would like to be all right. 

Thank You again for support !

Zoltan