3M M2256PW 用户手册

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3M™ Multi-touch Display M2256PW User Guide 
 
21 
3M Touch Systems, Inc. Proprietary Information – 37531 Rev D
APPENDIX A 
3M™ PX USB Controller Communications 
This appendix is intended for software developers only and discusses the fundamentals 
of communicating with the PX controller.  The firmware commands, which are usually 
issued by a driver or utility program on the host system, control the operation of the 
controller.  This appendix lists the recommended firmware commands and describes how 
to use each of these commands. 
Overview of USB Firmware Communications 
Developers may use this information when writing touch applications, developing 
custom drivers or touch configurations, or testing their touch systems.  Developers can 
issue commands to initialize the controller, select operating modes, and execute 
diagnostic functions. 
Note: This document assumes you are familiar with USB standards and modes of 
communication with USB devices, as well as firmware commands and how to use them.  
Executing some commands may alter the performance of your sensor and render it 
inoperable.  You should be aware of the results before executing any firmware 
commands. 
To optimize the performance of the PX controller and simplify the development of 
custom drivers, 3M Touch Systems recommends you use the commands listed in this 
appendix for current development.   
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 PX 
controller is USB Rev 2.0 full speed. 
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