The 1.5kOhm resistor is used to allow the PC to detect that a new full speed USB device has been connected to the USB port. This resistor must be used for the device to enumerate over USB. This is defined in section 7.1.5.1 of the USB specification.
The 1.5kOhm resistor is used to allow the PC to detect that a new full speed USB device has been connected to the USB port. This resistor must be used for the device to enumerate over USB. This is defined in section 7.1.5.1 of the USB specification.