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Preliminary Data Sheet, Rev. 5 USS-720
Instant USB
September 1999 USB-to-
IEEE
1284 Bridge
Lucent Technologies Inc. 5-13
USB Port (continued)
Vendor-Specific Requests
Vendor-specific requests supported by the USS-720.
Table 17. Vendor-Specific Requests
Label bmRequestType bRequest wValue wIndex wLength Data
GET_1284_REGISTER 11000000B 3 Address Zero 7 Register Data
SET_1284_REGISTER 01000000B 4 Address Data Zero Zero [None]
GET_1284_REGISTER
The high byte of the wValue field specifies the address
of the register that is to be read. The USS-720
responds by returning the current values in all of the
parallel port registers. This command is only supported
in interface 0, alternate setting 2. Attempts to issue this
command to alternate settings 0 or 1 will result in a
stall.
SET_1284_REGISTER
The wValue field specifies the address of the parallel
port register to be written in the high byte and the value
to be written in the low byte. This command is only sup-
ported in interface 0, alternate setting 2. Attempts to
issue this command to alternate settings 0 or 1 will
result in a stall.