Zybo-Z7 Device USB not recognized on PC Host

[Yaagyanika Gehlot]

Hello,

I'm trying to communicate between host (Windows PC) and device (Zybo Z7-20) with micro USB.

I have followed the instructions through this link.

However, while testing, when I connect the micro USB,

1. No power to Zybo: No recognition

2. Power to zybo: No recognition

3. Power, FPGA program through Xilinx SDK: Recognized as "USB Device" in drive.

4. Disconnect power and re-connect power: No recognition

Further info on point 3: When the micro USB is recognized as USB device, it asks to format the drive every time with an error as "E:\ The directory name is invalid".

Q1: I understand permission to format is a general procedure, but is it supposed to happen every time I plug in the micro USB?

Q2: Isn't it supposed to be recognized as a removable device? When I open device manager, it is recognized under Disk drives as "Xilinx PS USB VirtDisk USB Device" rather than under Ports.

Q3: After creating the BOOT.bin and loading into SD Card, JP5 has to be set on SD. Do I follow the same procedure to program after that? That is from Xilinx SDK -> Program FPGA -> Run As -> Launch on Hardware ?

I'm a newbie to FPGAs altogether, so apologies if the questions are dim.

Thanks in advance.

Edited February 1, 2022 by Yaagyanika Gehlot

[JColvin]

Hi @Yaagyanika Gehlot,

8 hours ago, Yaagyanika Gehlot said:

3. Power, FPGA program through Xilinx SDK: Recognized as "USB Device" in drive.

When you say recognized as "USB Device" in drive, are you referring to the Windows Device Manager? The Zybo Z7-20 should be recognized as a USB Serial Converter A and USB Serial Converter B under the Universal Serial Bus controllers dropdown, with a Bus reported device description of "Digilent Adept USB Device" in the Details tab of their Properties.

The fact that Windows is asking you to format the board at all is not what you should be saying when you are simply going for basic communication is concerning. Are you connecting the microUSB cable to the correct PROG/UART port (J12, just below the on/off power switch) or the USB OTG port (J10 on the underside of the board beneath the Type A USB port)?

Or am I misunderstanding your intended application entirely and you are actually wanting to use the Zybo Z7 as USB Communication Device and not just send serial terminal data to the host computer?

Thanks,
JColvin

[Yaagyanika Gehlot]

Hi @JColvin,

My application is to use Zybo Z7 as USB Communication Device. With Zybo as the device and a windows pc as a host. For that I'm using J10, on the other side of the board (below USB OTG).

Yes, I've attached screenshots for you to understand better.

This is from Device Manager under disk drives:

This is on My PC after formatting, "USB Device": 

As far as I understood it should've been recognized as a virtual port. But it's not. Is that correct? Neither does this come up in tera term. The USB Device is formatted as FAT.

Thank you for replying.

Please let me know if anything is unclear.

[JColvin]

Hi @Yaagyanika Gehlot,

You made your intended application clear, thank you.

I read through the application guide you linked more carefully, but I don't think I'll be of much more help as Digilent has not done this sort of application with our Zynq devices. I tried out the pre-made .bin and various files in the hopes that they would still be compatible with the Zybo Z7-20 even though the board it was designed for was a different Zynq 7020 chip, but no luck (i.e. the Zybo Z7 lit up the LED indicating that it read the SD card, but there was no sign of activity in the serial terminal). It also didn't help that their provided Windows driver for the CDC ADM driver is not compatible with Windows 10, or at least Windows reports that the driver is incompatible when I try to load it.

In terms of your initial specific questions:
1. no I don't think you should be asked to format the device every time you connect it
2. I would expect it to be recognized as a removable device, though I have not read the USB CDC ADM protocol specification to be able to speak confidently.
3. Once you have the boot.bin (and the image file if you are using Linux rather than baremetal), you should just be able to load the necessary files on the SD card and then connect over a UART serial connection (or the USB connection) with no need to open SDK at all.

The engineers over on the Xilinx forum might have some more insight on their application.

Thanks,
JColvin

 

[Yaagyanika Gehlot]

Hi @JColvin,

Thank you for replying and helping me through.

5 hours ago, JColvin said:

The engineers over on the Xilinx forum might have some more insight on their application.

Alright, I'll try that. If I do find a solution I'll post it here for future users.

Thanks,

Yaagyanika Gehlot.