FAQ_MA35_Family_USB Host Eye Diagram

[ytliu6]

There is an open source test command in U-Boot and you can utilize it to measure USB eye diagram
First, you need to enter U-Boot stage and following the below command.

Start the USB:

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$ usb start

Common USB commands:

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- usb start:
- usb reset: (re)starts the USB. All USB devices will be initialized and a device tree is build for them.
- usb tree: shows all USB devices in a tree like display
- usb info [dev]: shows all USB infos of the device dev, or of all the devices
- usb stop [f]: stops the USB. If f==1 the USB will also stop if an USB keyboard is assigned as stdin. The stdin is then switched to serial input.

Test commands:

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usb test [dev] [port] [mode] - set USB 2.0 test mode (specify port 0 to indicate the device's upstream port) Available modes: 
J, K, S[E0_NAK], P[acket],F[orce_Enable]

# usb test 1 1 P
Device 1
Port 1
Mode P

If you need to test another USB port, please reset the chip and re-enter the above commands.

#USBH #Eye Diagram