VIPER Technical Manual

Detailed hardware description

 

 

USB host interface

There are two USB interfaces on the VIPER. These comply with the Universal Serial VL Bus Specification Rev. 1.0a, supporting data transfer at full-speed (12 Mbit/s) and low-

speed (1.5 Mbit/s).

There are four signal lines associated with each USB channel:

•VBUS

•DPOS

•DNEG

•GND

Their arrangement is summarized in the following illustration:

USB Type A Plug 1

 

VBUS 1

 

 

PL7

 

 

VBUS 2

USB Type A Plug 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

2

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

1

 

 

 

 

 

 

 

 

 

 

 

DNEG 1

 

 

 

 

 

DNEG 2

 

 

 

 

 

 

 

 

 

 

2

 

 

 

 

DPOS 1

 

 

DPOS 2

 

 

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

GND

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(SHIELD) 9

10 (SHIELD)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

A USB power control switch controls the power and protects against short-circuit

conditions. See the section USB361Hpower management, page 362H83, for details of control.

If the USB voltage is short-circuited, or more than 500mA is drawn from either supply, the switch turns off the power supply and automatically protects the device and board. The VBUS power supply is derived from the VIPER +5V supply.

If you require details for the USB bus, or would like to determine whether particular peripherals are available, see www58H.usb.org.

© 2007 Eurotech Ltd Issue E

60