3M Touch Screen Controller RX181, Справочное руководство

Страница: 16 / 31

16 3M™ MicroTouch™ Controller RX181 Reference Guide
3M Touch Systems, Inc. Proprietary Information
Communication Basics
This section provides information on sending firmware commands to the controller and
interpreting the responses that the controller returns. The default operation of the RX181
controller is USB Rev 1.1.
The USB command set is implemented by using vendor requests and vendor reports, i.e.,
vendor specific transactions. The controller issues some reports without prompting the
computer. The computer can also send requests to the controller to change how it
operates or receives information about the controller. The controller issues a synchronous
report in response to some of these requests.
You need to know product ID (0100H) and the vendor ID (0596H) to write your own
driver. These values are required for identifying the controller.
The RX181 command set utilizes the HID protocol. The HID protocol allows the
controller to be used on most computers with operating systems that supports HID. The
only required software is a calibration tool used for aligning the sensor to the display.
This calibration tool is available from 3M Touch Systems.
Receiving Reports from the Controller
The controller sends a variety of reports to the computer. The first byte of each report is
the Report ID that defines the structure and content of the report. The controller sends
some reports as a direct response to a computer request (synchronous). The controller
will also send some reports as the result of an external event, such as a touch
(asynchronous).
HID and Packed Touch Reports
The controller sends to the computer reports in response to touches on the sensor. The
controller normally uses the HID-compatible report. In addition to the HID-compatible
report, there are two versions of packed report available. These versions return up to two
points of data per touch, as opposed to the one touch point in the HID-compatible report.
The first byte of each report contains the Report ID as shown in Table 3. You can use the
Set Asynchronous Report request to toggle between report types.
Table 3. Asynchronous Reports
Name Report ID Description
REPORT_ID_HID 1 HID-compatible coordinate data
REPORT_ID_PACKED 2 Packed coordinate data for custom
driver
REPORT_ID_UTILITY 7 Packed coordinate data for utilities
Only custom drivers and software can make use of the packed coordinate format. Refer to
the Set Asynchronous Report section for details on using packed coordinate data.