You can left it unconnected or You might want to connect it to 3.3V using 0 ohm resistor(I recommend). FX3 firmware can select whether to use VBUS or VBATT to Power USB transceiver. Generally Battery is used to power FX3 in case if it is acting as Host in OTG mode, where battery voltage can vary to large extend. If you look at the DC spec in the Datasheet , you can find that VBATT range(min-max) is more than VBUS.

Does the firmware select between VBUS and VBATT automatically (checks, which has voltage)?

Or what is default power supply input, when connecting new device first time to USB host  with boot from USB option (no memory with firmware)?

I have VBATT input open and USB host don't detect CYUSB3014 connected.

I can transfer a image file with the USB Control Center, I got Programming Succeded, but no new device appears in WIndows device manager. I have no complete schematic diagram on the EZ-USB FX3 Development Kit, so it is tricky to find differences in my design versus Dev.kit.

I power the VBUS pin, the VBAT is floating. I have read that the firmware selects power supply pin for the transceiver part, but not found more information so far. I had a quick look in the source files but did not find any power configuration related.

I want to test if the problems is caused by "wrong supply pin for the project" by connecting also VBAT to incomming 5V.

Can the internal regulator handle supply voltage on both VBAT and VBUS simultaneously?

Best regards

/Pär

http://www.cypress.com/?app=forum&id=167&rID=64886

Hi Pär,

Yes. You can connect both VBUS and VBATT simultaneoulsy.

I think your problem might be solved if you connect VBATT to 5V.

Regards,

Sai krishna.