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3M™ Multi-touch Display M2256PW User Guide 27
3M Touch Systems, Inc. Proprietary Information – 37531 Rev D
Set Feature –Restore Defaults
This is a request to restore parameter defaults.
Table 13. Restore Defaults -- Setup Stage
Offset Field Size Value Description
0 bmRequestType 1 0x21 Class,H2D,Interface
1 bRequest 1 0x09 Set Report
2 wValue 2 0x0303 msb=03=Feature
lsb=03= Feature Report ID
4 wIndex 2 0 Always 0
6 wLength 2 8 Always 8
Table 14. Restore Defaults - Data Stage
Offset Field Size Value Description
0 Report ID 1 0x03 Feature Report ID
1 Report Subtype 1 0x08 Restore Defaults
2-7 6 0 Not used
After sending this command, the controller will acknowledge (ACK) the transfer, but the
command will not yet be completed. Before sending any other commands, the host
should poll with GetStatus until the command status field returns “Command Complete”
or “Fail”. Any timeout for this status polling should be 2 seconds minimum.
Asynchronous Reports
Coordinate Data – MultiTouch Digitizer mode Async Report 0x13
This is used to transfer the coordinate data to the host. This report, when activated, is
sent to the host whenever new data is available/scheduled for transmission. It is an
asynchronous report that is activated by default at power up. See SetAsyncReport for
details on how to activate/deactivate an asynchronous report.
The report shown supports up to 6 simultaneous touches. Note that if more than 6
touches were to be supported, Report 0x13 would be sent as many times as necessary to
accommodate the number of fingers touching. Only the first Report 0x13 will have a
non-zero actual count. Each valid touch is marked with an ID number that remains the
same from touchdown thru liftoff. The ID number can be any value from 0 to 255. Ignore
all other data within a touch report structure with a status marked “not valid”.
The coordinate system is Upper Left origin.