Usb Command Set - 3M Touch Screen USB Resistive Controller SC500 Reference Manual

18
Table 6. Coordinate Data Report Touch Status Byte
Bit
0
1
2
3

USB Command Set

The USB command set is implemented by using HID Get Feature and Set Feature
commands. The various requests and reports are grouped together by report size
under a common feature ID.
The commands listed below are those that 3M Touch Systems currently use for
communications. 3M Touch Systems recommends that you use only these commands
for SC500 USB controller communications.
Sending Commands to the Controller
To send a command, the computer must construct a USB packet for sending to the
controller. The general packet format is described in Table 7. Any data appended
immediately after this data is referred to as the data stage of request.
If using the Windows you may want to use the Set and Get Feature functions. The
buffers are the same except the first two fields. The bmRequest Type and bRequest
fields are omitted, thus making wValue the first field. For your convenience, each
command is labeled as either a "Set Feature" or "Get Feature" command.
Status
0 = not touching, 1 = touching
0 = data invalid, 1 = data valid
Not used
Not used
3M Touch Systems Proprietary Information
SC500 USB Controller Reference Guide