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Micro-SD cards for Zynq Ultrascale+ EV

gilbert.lopez

We have been using SanDisk 8GB UHS-1 cards with no issue until recently. Our latest board is failing to boot, and I found this document which states the UHS-1 is not optimal for this:

https://avtinc.sharepoint.com/teams/ET-Downloads/Shared%20Documents/Forms/AllItems.aspx?id=%2Fteams%2FET%2DDownloads%2FS…


However, I am having trouble finding any of the recommended cards that are listed there. Is there a more up-to-date / revised version of these recommendations? Our procedure is quite simple, we create a 2GB bootable FAT32 BOOT partition, and the rest of the card memory is used for an ext4 rootfs partition.

 

Any help would be greatly appreciated.

  • 0

    Hi there,

     

    I am glad you found that document!  So far, there was not any updates, but I can say the below two links are the card types that I have tested.

    I use 8GB+ and have used both Utility+ and Utility types.  Based on recent updates to PetaLinux, I would suggest anything over 16GB.  NOTE that officially 32GB is a boot limit in order PetaLinux's and Xilinx documentation.  However, we have tested (in some cases, but not enough for me to state 'always works') up to 128GB.  The test I recall seeing was on Ultra96V2, which is a 3EG device (same as UltraZed-EG).

     

    Delkin Utility MicroSD

    Delkin Utility+ MicroSD

     

    The main difference is the Utility+ is Industrial temperature rated.  Unless you are using an I-grade SOM, a Utility is MORE than adequate.

     

    --Dan

  • 0 in reply to drozwood90

    Thank you so much for the response. Is there any issue that these all seem to be UHS-1, and that those are not recommended according to the above guide?

  • 0 in reply to gilbert.lopez

    Hi there,

     

    Great question.  If you look at page 8, all of those cards have been purposefully tested.  There is some wiggle room in the complex SDCARD specs, and as such the guidance was to NOT use UHS-1.  This is because of how cards are specified and the minimum levels of performance / features that qualified a card to get such a marking.  In practice, the cards you were using, the card can be changed without your knowledge.  As long as it continues to meet that minimum specification, they can be sold as the same regardless of the onboard firmware, or flash type/configuration. 

     

    The Delkin card is BOM controlled.  If you use that card, which has been tested, you can be assured that you are getting the same card throughout the purchase cycle and it will always have the same firmware, memory type etc.  If there is a change, it is treated like any other component on the board.  It is a bigger deal to Delkin than typical "consumer" level parts.

     

    Also, note that since that document was produced, the two Xilinx documents that are listed have since changed.  I eluded to this in my previous response.  I would highly suggest taking a look at the latest document to help assist you in your research and edification.

     

    All that being said, the Delkin Cards I linked to have been tested and since they are BOM controlled - if you ensure you use that SAME part number, you will always get the same thing.  That is one the things that Delkin provides as a value to customers.

    You can read more on this from the Storage Insights series:

    Storage Insights #1 - Why Not All SD Cards are Created Equal

     

    --Dan

  • 0 in reply to drozwood90

    I understand you don't need the larger cards, but since Dan mentioned it, I'll add a little for any other readers. I have successfully boot tested both the 64 GB and 128 GB Delkin Utility cards on the Ultra96-V2. Like Dan said, that is a 3EG device, but I expect it would work on any ZU+ architecture. Newark has the 64 GB cards in stock, and the 128 GB cards can be special-ordered either through Newark/Farnell or Avnet. Newark is in an outstanding stock position for people to prototype with these cards with stock on everything from 8 GB to 64 GB. For your long-term production needs, you can also ask your local Avnet representative to quote these.

     

    One other note relates to the BOM-controlled nature of the Delkin cards. You can get your cards pre-programmed through Delkin, with a custom-assigned PN, which further locks down the device. That way, you are getting the exact same hardware, firmware, and programming on every individual card. If you are interested in pursuing Delkin programming services, you can work out the details and cost through your local Avnet office.

     

    Bryan