Do USB Interfaces Need Pull-Up Resistors?
It is common to see pull-up and pull-down resistors connected to the D+/D- lines of USB interfaces on some development boards, while others do not connect anything at all. This can be quite confusing. On the official USB protocol website, http://www.usb.org/developers/docs/usb20_docs/#usb20spec I checked the resistor_ecn document. First, the USB bus can have both idle and … Read more