Teledyne LeCroy HPT - Users Manual - Manual (Page 10)

CATC HPT User’s Manual Version 2.27
Page 8
5.2.4 Set Configuration
The application program sends another standard device request (“SET_CONFIGURATION”)
message. After receiving this request, the HPT test device sets its current configuration to 1,
enables bulk transfer endpoints 1, 2, 3, and stands by to send and receive through bulk transfers.
5.2.5 Bulk Read
The HPT test device now sends a 64-byte IN packet through endpoint 1: data 0x00 through 0x3E,
plus a final byte that reflects the power status of the two USB ports on the test device (see “USB
Power State Test” below for discussion of power status). This step is performed twice (i.e., two
64-byte transfers).
Last Byte Port 1
Power Status
Port 2
Power Status
0x3F Good Good
0xF0 Bad Good
0x0F Good Bad
0x00 Bad Bad
5.2.6 Loopback Test
The HPT test device is programmed to send back to the host, through endpoint 2, the same data it
receives from the host through endpoint 3. In the loopback test, the USB HPT program sends a
16-byte OUT packet through endpoint 3 followed by a 16-byte bulk read (to read the data back
from endpoint 2). This step is also performed twice (i.e., four 16-byte transfers; two OUT and
two IN). The program checks that all data received correspond to the data sent.