3M M2256PW manual Asynchronous Reports, Set Feature -Restore Defaults

3M™ Multi-touch Display M2256PW User Guide 27

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.

3M Touch Systems, Inc. Proprietary Information – 37531 Rev D