SD Card Boot Issue On Custom Carrier Card

[msattine]

Hi,
   I am trying to bring up a custom carrier board with TE0807 on it.

The JTAG boot is found to be working fine upto PS configuration, while PL configuration is still an issue. It throws error "DONE signal is not set HIGH" and the RED LED on TE0807 remains ON.

Observing another issue with SD card boot. I am not observing any messages on UART and the RED LED remains ON. When I read status registers from PS, I figured that CSU_BR_ERROR is set indicating an issue with SD BOOT.

Then I probed SD card interface signals and found that the response for CMD8 is wrong and then there is no further transaction on the interface.

I am really stuck here and any help is appreciated.

-
Mohan.

[JH]

Hi,
which carrier did you use?

In case of our TEBF0808, can you please try out  prebuilt Boot.bin and image.ub from our newest Reference Design (2019.2):
https://wiki.trenz-electronic.de/display/PD/TE0807+StarterKit

br
John

[msattine]

Hi John,
         I have used the same SD card and same image on TEBF0808 carrier board and it worked. But I am not pointing to this carrier card above.

The issue is when I am trying to use the same image and SD card for a custom carrier board that we built for our product. The IO mappings for SD card are similar and so I expect that atleast the loading of the image from SD-card to OCM should happen.

To add further, QSPI flash is working fine on this board.

I am sure that there is something to do with the SD card side as it is not properly responding for CMD8.
I did verified that power levels at SD card interface are all good.

Any other debug suggestions to root cause this?

-
Mohan.

[JH]

Hi,
which kind of level shifter did you use?
can you share the part of schematics with SD connection?
How did you set boot mode pins?

br
John

[msattine]

Hi John,
   I have set BOOT Mode pins to 0101. I also confirmed this by reading PMU registers.

Attached the SD interface part of the schematic.

I can see that the BOOT code started initialization of SD card and as there is no proper response from SD card, the BOOT is halted indefinitely.
As I mentioned earlier SD card is not responding properly for CMD8.

-
Mohan.

[JH]

Hi,

it's your levelshifter, you need one which supports SD.

br
John

[msattine]

Hi John,
  But we used this in another project and it worked there. And the connections are maintained here too.
Is there any specific reason why you are saying this?

Regards,
Mohan.

[JH]

Hi,
your other project is also Zynq or ZynqMP?

It's not the first time that we see that somebody has trouble with SD when he use a normal level shifter.

We only use level shifter which supports SD (and as I know Xilinx too --> you ca check schematics of the Xilinx eval boards).

br
John

[msattine]

Hi John,
           Yes, the other board is also with ZynqMP. Only difference being its TE0804 on older board and TE0807 on newer one.

I probed SD_CMD on both sides of level shifter and I do see a point where the host side pin is not tracking device side pin. And this is the reason for CMD8 failure.

So what you said looks to be correct. But I am still wondering why the same configuration worked on older board.

-
Mohan.

[JH]

Hi,

But I am still wondering why the same configuration worked on older board.

Maybe just luck? Routing, trace length... also influence signal and the SoC also have tolerances(did you use it only with one TE0803 or different modules?).
PS: I didn't know your carrier PCB design, but in general TE0808/TE0807/TE0803 are compatible, so you can check SD boot also of your older carrier for TE0803

At the end I would recommend to use levelshifter which supports SD, this make normally less trouble.
br
John

[msattine]

Hi John,

We are using SD-boot on the other board (with TE0804) and we have multiple of them working with SD-boot.

And we tried SD-boot on multiple new boards and the observation is the same. So, we are now concluding it to be a level shifter issue.

Thanks! for all the help.

-
Mohan