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USB Low-Full-High Speed Peripherals

JeBo_4132831
New Contributor II

Hi,

Another day, another question 🙂

I'm always on the same FX2LP18 board. Today, Firmware works in a Bus-Powered mode. 

I would like to add a Self-Powered capability to the firmware. The board is able to take the power either from the USB or from a Power Supply. I can monitor the USB_PWR through an I2C component by reading a register on it  (not directly using a PIN of the FX2LP18).

In Self-Powered Mode, What i need to do exactly onto firmware side, upon detection of USB_PWR ? 

Clear and set DISCON bit ?

Thanks.

 

Regards.

 

 

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1 Solution
PranavaYN
Moderator
Moderator

Hi,

Yes, you need to set DISCON if VBUS is not present and clear it when VBUS is present.

Please refer to Powering USB Devices section in the following appnote - https://www.cypress.com/documentation/application-notes/an15456-guide-successful-ez-usb-fx2lp-hardwa...

Here VBUS is monitored using a GPIO and DISCON bit is set/cleared accordingly.

Best regards,
Pranava

View solution in original post

1 Reply
PranavaYN
Moderator
Moderator

Hi,

Yes, you need to set DISCON if VBUS is not present and clear it when VBUS is present.

Please refer to Powering USB Devices section in the following appnote - https://www.cypress.com/documentation/application-notes/an15456-guide-successful-ez-usb-fx2lp-hardwa...

Here VBUS is monitored using a GPIO and DISCON bit is set/cleared accordingly.

Best regards,
Pranava

View solution in original post