High and Low Levels Transmit On low and full speed devices A differential ‘1’ is transmitted by pulling D+ over 2.8V with a 15K ohm resistor pulled to ground and D- under 0.3V with a 1.5K ohm resistor pulled to 3.6V. A differential ‘0’ on the other hand is a D- greater than 2.8V and […]

Windows USB Diagnostic Tools www.uwe-sieber.de/files/UsbTreeView.zip Unzip it and for 64 bit Windows you simply run USBTreeView.exe in the x64 folder (you don't need to install it). To use on a clients system ask them to go to "File > Save Full Report" and send this report to you.  

USB Org resources The full spec and downloadable tables etc can be found here (Device Class Definition for HID). Get the 'HID descriptor tool' from the same page to help create descriptors – very handy!!! Overview A USB HID Report Descriptor is requested by a USB host from a USB device.  It tells the host […]

USB To Mini Round DC Power Cables http://www.lindy.co.uk/cables-adapters-c1/usb-c449/usb-power-c1518/1-5m-usb-to-2-5mm-inner-5-5mm-outer-dc-adapter-cable-p7253 http://www.lindy.co.uk/cables-adapters-c1/usb-c449/usb-power-c1518/1-5m-usb-to-1-35mm-inner-3-5mm-outer-dc-cable-p7252 ​http://www.lindy.co.uk/cables-adapters-c1/usb-c449/usb-power-c1518/1-5m-usb-to-0-7mm-inner-2-3mm-outer-dc-cable-p7251

The Power Request Made within the USB CONFIG DESCRIPTORs.  You can have more than one with different power requests, but host devices may not support dealing with multiple configurations. General Power Availability A device that wants to be able to function on all systems and hubs should request 100mA max.  Multiple Power Configurations One solution […]

The +5V output from a USB hub is permitted to range from 4.75V to 5.25V (5V +-5%).  For USB2.0 this range is changed to be 4.4V to 5.25V and for USB3.0 the range starts from 4.0V. A USB device is permitted to draw up to 100mA (1 unit load) for USB2.0, and up to 150mA […]