3M Touch Systems Proprietary Information
CHAPTER 3
EX II Controller Communications
This chapter discusses the fundamentals of communicating with the EX II controller. The
firmware commands, which are usually issued by a driver or utility program on the host
system, control the operation of the touch screen controller, however developers can enter
these commands directly. This chapter:
•
Describes the controller default settings.
•
Lists the recommended firmware commands for current development.
•
Describes how to use each of these commands.
•
References additional commands developers may need to use.
The description of each command includes the command syntax, the default value, how
the command works, and the expected response from the controller.
Controller Default Settings
Communication Parameters
The default operation of the EX II controllers is N81 (no parity, 8 data bits, and 1 stop
bits) at 9600 baud. The EX II 1720SC can be programmed to work with even/odd parity,
7 data bits, and 1 or 2 stop bits.
Data Format
Data format
refers to the type of packet the controller uses to send the X/Y touch
coordinates to the host system. Format Tablet is the default format for the EX II
controller. In Format Tablet, the controller sends 5 bytes per point and provides the most
rapid response time to a touch.
•
Format Tablet is supported by all current 3M Touch Systems touch screen
controllers.
•
It is the standard for current 3M Touch Systems product development and is the
format used by all touch screen drivers written by 3M Touch Systems.
Refer to the Format Tablet command in the firmware reference section. Note that both
TouchWare and MT 7 software automatically set communications parameters to N81.
