USB SERIAL BUS STANDARD TO INTERFACE DEVICES Allow

USB • SERIAL BUS STANDARD TO INTERFACE DEVICES • Allow devices to be connected with single std. scoket • Allow plug n play i. e connecting and disconnecting without rebooting computer • i. e hot swapping Visit for more Learning Resources

Low power consumption No need of external power supply Allow devices to be used w/o drivers installed Can connect mouse, k/b, joystick, cameras, printers, scanners. . • Designed by USB_IF(incorporating Forum) • V can install and remove devices without opening case • •

Usb is better than RS 232 • • Easy installation Fast transfer rate Simple cabling Multiple device connection

versions • Low speed 1. 5 mb/s used for k/b, mouse, joystick • Full speed 12 mb/s USB 2. 0 FCFS rule for many devices • Hi Speed of 480 mb/s • Super Speed 4. 8 Gb/s

Features • • Host Multiple devices 127 Cable length 5 to 30 m Transfer rate 12 mb to 480 mb/s Ease of installation Hot swappable plug and unplug anytime Hot pluggability BIOS feature allow to plug n play

• Power saving • Support wide range of devices • Hub architecture

Connectors & cables • • • A upstream towards computer B downstream to individual devices Max length of cable is 5 m 26 ns delay is maximum Contains 4 wires VCC red +5 v D- white Data. D+ green Data+ GND Black Ground

Usb process • Host queries all devices and assigns address to each is called enumeration • Each device transfer different data • 1)Interrupt little data mouse, k/b • 2)Bulk data in one big pkt printer 64 byte • 3)Isochronous streaming devices example speakers • USB divides BW into frames first for isochronous nd remaining for other bulk and interrupt For more detail contact us