Teledyne LeCroy HPT - Users Manual - Manual (Page 11)

CATC HPT User’s Manual Version 2.27
Page 9
5.2.7 Connection/Disconnection Ability
The application program sends a device specific request to allow the HPT test device to
disconnect itself from the bus and to reconnect after a short period as either a full- or low-speed
device. The HPT program checks the port status registers to ensure that both disconnect and
connect events concluded properly.
5.3 USB Power State Test
The HPT test device checks that the USB host is supplying 5V DC power on the USB bus,
between the power and ground pins of the USB connectors. (The test device does not measure
the amount of DC current supplied by the USB host.) During each port test sequence, the HPT
test device sends power state information for both USB ports to the host. The application collects
and compares this information, and displays it at the end of the test. If all (two or four) functional
test sequences fail, the application displays “N/A” for the power state.