PicoZed 7020 eMMC initialization

EniX2000 over 1 year ago

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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flyingbean over 1 year ago in reply to EniX2000 +2

You need to connect SD card CD(card detect) and WP(write protect) to SDIO controller on Zynq. One example is as below: Here is one of FPGA projects I did on MiniZed for SD card data storage: You…
flyingbean over 1 year ago in reply to EniX2000 +1

The short answer is NO
flyingbean over 1 year ago in reply to EniX2000 +1

eMMC needs a boot.bin programmed on it. This boot.bin can be bare-metal type. However, you do need Linux boot.bin on either SD card or QSPI flash to boot Zynq FPGA first. Then you use this Linux to program…

flyingbean over 1 year ago

eMMC initialization has to be done after Linux booting up. So you need either to boot PicoZed from SD card or from QSPI flash memory first, then log into Linux to initialize eMMC.
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EniX2000 over 1 year ago in reply to flyingbean

Hi,

Thank you for your answer.

My application is bare metal so I use no Linux OS.

Is there any way to initialize the eMMC from a bare metal system ?

Many Thanks,
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flyingbean over 1 year ago in reply to EniX2000

The short answer is NO
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EniX2000 over 1 year ago in reply to flyingbean

OK, could You be more specific please ?
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flyingbean over 1 year ago in reply to EniX2000

eMMC needs a boot.bin programmed on it. This boot.bin can be bare-metal type. However, you do need Linux boot.bin on either SD card or QSPI flash to boot Zynq FPGA first. Then you use this Linux to program eMMC bare-metal boot.bin into eMMC. I might need draft a HOWTO for the topic for this community. I hope you might find some HOWTO before I do it. Here is one HOWTO on eMMC programming: https://www.beyond-circuits.com/wordpress/tutorial/tutorial27/
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EniX2000 over 1 year ago 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!
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flyingbean over 1 year ago 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.
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EniX2000 over 1 year ago 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,
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flyingbean over 1 year ago 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:

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

Here is the snapshot of sD card used as a data file system.
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EniX2000 over 1 year ago 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!
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