02-03-2021 05:41 AM
I need some help/guidance as I have some problems with two of our ZYNQ ZC706 boards where I want to Boot from SD-card.
In our company we have multiple Zynq zc706 boards one with v1.0 and 3x with version 2.0. With two of the v2.0 boards I’m not able to boot.
The terminal (UART) does not display anything and the “init’ led is changing to red.
The Boot.bin and image.ub on the SD card is working as I can boot with this combo on our zc706 v1.0 board and one of the other zc706 v2.0 boards.
Currently I’m out of ideas and I have the impression that it should be something board related.
Please can you provide more information what root cause can be and what I can do to resolve this?
Thanks in advance.
02-03-2021 08:04 AM
This link provides a good place to start debugging:
Step 3 in particular might tell a lot.
You should also always start by ensuring that you can program your boards in JTAG mode with a simple "Hello World" application, or something similar. You're assuming you have a boot issue, but that might not be the main problem at all. The more things you can verify/rule out, the easier it will be to get to the root cause.
02-03-2021 11:34 AM
Thanks for your prompt reply. I will have a look at the you referred to.
What is not clear to me is why one sd-card with an image boots on one board (hardware in PL is accessible) and does not boot on an second identical configured (switches/jumpers) board.
Can you elaborate more on possible root causes?
02-03-2021 12:26 PM
Can you elaborate more on possible root causes?
Honestly, at this stage, not really. There's not enough information to go on. Like I said, it's hard to know if it even is a boot problem. To talk about root causes now would just mean listing out all the related fundamental parts of the board that can go wrong (PDN, clocking, SD card cct, etc), but it's just guess-work. (Although it does sound board-related, as you said.)
Out of curiosity, did the boards ever work, or is this a new batch? Were they sitting in a dusty corner for a few years? Did somebody damage the boards and not bother marking them as such?
02-03-2021 02:47 PM
Here's another thread that might help you in your debugging steps:
Also, another great tip, which I saw posted in a different thread by @denist:
Check if the SD clock starts. It should go to ~200KHz at first, then 8MHz and later on to 50MHz.
Depending on the last value you see, you should focus the debugging differently.
For example: If it's stuck at 200KHz it means the initial configuration (based only on CLK and CMD line) was incorrect. Most likely an HW issue if so.
If it stops at 8MHz, the bootROM is failing transferring data. Check the data lines.
02-03-2021 11:52 PM
"Out of curiosity, did the boards ever work, or is this a new batch? Were they sitting in a dusty corner for a few years?"
Sorry I did not mentioned this. What I know for sure is that one boards is used actively (last couple of days). When I replace the image on the SD-card with one of an other project both failing boards are able to boot and the "init' led turns green as expected.
|Board||Image new||Other image.|
|ZC706 v2.0 board 1||boots||boots|
|ZC706 v2.0 board 2||does not boot||boots|
|ZC706 v2.0 board 3||does not boot||boots|
Thanks and regards,
02-04-2021 02:27 AM
Okay, so it may be boot-related. Here are some things I would try:
1. On the bad board(s), see what happens when you download the bit-file/ELF in JTAG mode.
2. For the SD card, build your new image with the FSBL_DEBUG_INFO option enabled and compare the results with both a good board and a bad board.
3. Also, build a really simple image for the bad boards (even just a "Hello World" app) and see if that also fails.
4. Compare the SDIO clock line activity on the good board and bad board (using the recommendation from @denist).
5. Analyse the SD card signals for the good and bad board; do the clock/data signals look noticeably worse on the bad boards?
6. On the two bad boards that are failing, see if they both fail at the same points (for example, using steps (2) and (4)).
7. Probe the supply voltage for the SD card circuit during boot. Ideally this should be done with a scope as the board is coming up, but at the very least use a meter when the board is up. As before, compare the results between the good boards and bad boards.
For some of those steps you need to be comfortable probing (or soldering probe options on) what is a relatively expensive board. Up to yourself if you want to do it!
02-12-2021 01:12 AM
Thank you for the information. This is definitely that I would like to try but is unfortunately this not something that I can work on immediately.
I will come back to this thread when I have more information after the investigation.
04-15-2021 10:00 AM
Further investigation turned out that it had to do with the selected DRR memory chips for the board.
Investigation which memory chips are actually used on the board we found a discrepancy between the chips on the board and how they where configured on the Processing subsystem.
After the correction, the board was booting up as expected and the mysterious 'red' light was disappeared.