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What to do with a USB VBUS line?
The ground connector on the USB will be tied to the board ground, and the D+ and D- lines will go to the STM32’s USB_DP and USB_DM with a pull up on the D+ line to signal full speed. What I want to know is what to do with the USB VBUS line.
How does host 5 V connect to Vbus pin?
The host 5 V connects through the USB cable to the VBUS pin on the PIC32 usb device. That is just how it is. So: You are operating your PIC32MX795 as a USB Device (not Host), and it is self-powered (doesn’t get operating voltage from the USB connector).
Where does the power come from for a VBUS?
The VBUS is meant to get power form the host computer, which then powers up the USB transceiver on the PIC when plugged in. You do not have to supply it power from the PIC side of things if it is a USB device. If this is not your scenario, you need to better explain your setup.
Does a self powered USB device have to connect to VCC from?
Consequently a self powered device downstream need only connect it’s local +5V to its VBUS in one of two ways: directly, and cut the VBUS line in the cable; alternately, wire OR local 5V + host VBUS, preferably with ideal diodes like the LTC4357* that regulate an NFET like the FDB3632 that regulate a 25mV drop.
What kind of power supply to use for VBUS?
Use an external power supply of 5V – 9V in place of the VBUS. There is an automatic switching circuit recommended by Microchip. Check its web site you will find a MOSFET automatic switching circuit: meaning that whenever you have an external power supply, VBUS would be cut off automatically.
Can a 3.3V power supply be used for a VUSB?
Use VBUS from the PC, step it down via a 3.3V linear regulator and outputs as Vdd as the power supply for the PIC18LF part if you want to use 3.3V as the Vdd. Vusb can be internally generated or using the same Vdd because it is 3.3V in your case.
Is the USB 3.3V for the Pic?
In the datasheet of the PIC it states that the USB is 3.3V however I measured the output from the PC’s port and the voltage lines read 5V. The device does NOT have to be powered from the USB it only needs to use it for communications purposes. 3.3V is for the internal transceiver built-in the PIC18-F or LF series with USB support.