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PicoZed 7020 eMMC initialization

EniX2000

Hi,

I have a PicoZed 7020 Rev E with 8Gb of eMMC memory. The application is bare metal.

I never used the eMMC memory before...

I would very much appreciate any ressource link on this topic (getting started tutorials, application notes or code examples).

Do you know if AVNET published somewhere initialization/formatting examples?

Best Regards,

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  • in reply to flyingbean

    Hi flyingbean,

    Thank you for your answer! 

    I apologize since I'm a newbie on eMMC questions.

    Please note that I do not need to boot from the eMMC memory. I just need to store and retrieve big chunks of log data.

    Under these circumstances placing a boot.bin file on the eMMC is the only way to proceed ?

    Can the eMMC be used without being formatted?

    I mean if I can write and read on the eMMC then I can pass on creating specific partitions.

    The default/factory configuration might be enough for me if I had some info on how to write it and read it afterwards...

    But I do not know if it's possible...

    Where i can find some good ressources on this matter?

    Thank You!

  • in reply to EniX2000

    If eMMC is not the booting memory/flash, you can use eMMC as a storage space. I don't know there is a master FAQ on eMMC for FPGA applications online or not. Even Avnet or Xilinx did not have a FAQ repo on eMMC topic. Strange?

    Here is the path for eMMC bare-metal driver: xiffs

    https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18841771/xilffs

    Xilinx xiffs driver is pretty user friendly. I used it for SD card project before.

    Yeah, I did know someone with more than 30 years FPGA experiences did not know eMMC very much since this folk never used eMMC before.. So your questions sounds reasonable to me.

    Can you use USB stick memory on PicoZed without formatting it? The answer is NO.  eMMC on PicoZed should be formatted at Factory before it is sold into market. However, will you still use the same format as the default factory setting? It is up to you. 

    Learning-by-doing. Feel free to post questions if you cannot find answers online.

  • in reply to flyingbean

    Hi there,

    Since using the eMMC is still a little foggy (lack of a good strart-up tutorial) I tried to store data on the uSD card. I already use the uSD card in order to boot.

     PROBLEM:  the uSD card appears to be write-protected when used with the PicoZed.

    The fopen function returns the code 10 (error).

    Otherwise I can write on the uSD the boot code without any problem. The write protection is active only whent the uSD is mounted on the PicoZed motherboard.

    Is there a way to programmatically  disable the write-protection in order to be able to create/write files on the uSD ?

    Regards,

  • in reply to EniX2000

    You need to connect SD card CD(card detect) and WP(write protect) to SDIO controller on Zynq. One example is as below:

    image

    Here is one of FPGA projects I did on MiniZed for SD card data storage:

    You may hard-code CDN and WP to be 0

    image

    Here is the snapshot of sD card used as a data file system.

    image

  • in reply to flyingbean

    Hi flyingbean,

    Thank You for your answer and detailed explanation.  The problem was on the WP indeed. It was allocated on MIO 50 but configuring this MIO as output and setting it to zero was not enough.

    I coded WP to zero as in your example and it worked!

    Thank You!