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TF1999

Zybo z7 usb uart no longer recognized by pc

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Posted (edited)

Disclaimer: I'm not an expert, just a student working on a school project.

My zybo z7 board stopped showing up as /dev/ttyUSBx on my linux vm when connected using the UART microUSB port. On my windows host the com port does show up but I cannot open a connection with putty (115200 8n1), no error info or strange characters, just an error sound effect with no explanation. I tried everything on the pc side (driver reinstall, reboot, enable/disable port, different ports, different cables) but I suspect that it is the board not communicating.

I use external power with WALL selected and booted from an sd card with a 500 mb fat32 partition with a boot and image file generated with xilinx petalinux which were not changed from when everything worked fine. There is also a 3gb ext4 partition where the fs is. The only thing that changed before the problem occured is that a few to-be-tested precompiled kernel modules where added to the ext fs in the home folder. Other students with the same set-up do not have this problem. I tried different sd cards and remade the partitions and redid the boot/image/fs generation but no success.

When booting from QSPI the example program works fine so I don't think the board is broken (The serial com doesn't work in QSPI either but I don't know if it's supposed to). Maybe it needs some kind of factory reset? Is there a way to confirm if the microUSB port is working? Help will be appreciated.

 

btw: upon startup I can see the RX led flickering but never the TX led

Edited by TF1999

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Posted (edited)

When you create a HW project in Vivado, you have to configure the Zynq. Since you are using a Petalinux build, the UART channel is enabled for sure in Zynq.

However I've built 2 demos to test the UART, because I don't know which Zybo Z7 you have. These are the files, select the one for you board:  

Zybo_Z7_10.bin

Zybo_Z7_20.bin

I'm using:

image.png.dcb8f7141bd379ca83750b4999da8dde.png

 

I know for sure that these 2 demos are working. Copy the .bin file to an empty SD card, rename the file to BOOT.bin, JP5 jumper set to SD on the board, wait for the DONE LED to become green. Press PS-SRST button to show the message multiple times on the serial console.

Let me know what you see

 

Edited by Ana-Maria Balas

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So let me understand, you can program the board via JTAG using the micro USB cable but you cannot access the serial port.

1. With the Virtual machine, you have to be careful to allow the USB devices to be connected to your VM. If the USB device is connected to the VM, then you cannot access it from Windows and if the USB device is connected to Windows, then you cannot access it from VM, in your case from Linux and that is why it is not detected.

2. Did you enable the UART MIO channel in Zynq ?

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Posted (edited)

@Ana-Maria Balas Yes, I programmed the FPGA with a tutorial example (I never used Xilinx SDK before) and it did auto detect the zybo board and I am able to run and debug the project line by line. It seems that the micro USB port is working fine. But neither Putty, Realterm or the Xilinx SDK terminal give any serial output (on my windows host without running vmware). The Xilinx console does however output some random characters (with 115200 baudrate) if I connect STDIO to console in the Run/Debug configuration.

I did not look into the UART MIO channel, how/where can I enable that?

Edited by TF1999
tagged Ana. Don't know if she'd see the reply if i don't

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Posted (edited)

Yes, it works! (It's the zybo z7 10 btw)

image.png.2a765a22f92faa5c7e45bf32018c9831.png

Does that mean that there is something wrong with the boot.bin I got?

Edited by TF1999

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Somehow the hardware project it is not configured properly for your board. You can check that by seeing if the DONE LED is turning GREEN for the BOOT.bin you got. Let me know

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I did some testing and it turned out to be a combination of wrongly configured boot files and vm - host serial connection mix-ups. Thanks for the help!

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