3M
™ Multi-Touch ASIC Controller Reference Guide
29
3M Touch Systems, Inc. Proprietary Information
To optimize the performance of the touch controller and simplify the development of
custom drivers, 3M Touch Systems recommends you use the commands listed in Table
19 for current development. Using these commands ensures compatibility with all 3M™
controllers.
Note:
When you enter commands in terminal mode, precede each command with
<CTRL> A to enter the start of header.
Table 26. Firmware Commands for PX5nnn Serial Controller Development
Command
Code
Description
Calibrate
CX
Initiates an interactive 2-point calibration.
Mode Down Up
MDU
Reports touchdowns and liftoffs only.
Mode Inactive
MI
Turns off touch reports.
Mode Stream
MS
Default mode. Streaming touch reports.
Null Command
Z
Returns an ACK. No effect.
Output Identity
OI
Returns Identity string: ADxxxx
Soft Reset
R
Resets certain modes and gets a new baseline.
Restore Defaults
RD
Restores default settings.
Unit Type
UT
Returns the Status string: AD****ss.
Calibrate
Syntax:
<SOH>
CX
<CR>
Response:
<SOH>
1
<CR>
Valid point response.
A Valid Point Response (‘1’) signifies that a touch coordinate was detected and is in
range of the expected screen target area. Two valid point responses indicate successful
calibration.
<SOH>
0
<CR>
Invalid point response
An Invalid Point Response (‘0’) is returned if the touch coordinate is out of range. If
either calibration point is invalid, the touch coordinates are discarded and the calibration
points remain unchanged from their previous values.
<SOH>
2
<CR>
Invalid point response
An Invalid Point Response (‘2’) is returned if the user did not touch the target long
enough to provide an accurate point.
Description:
Initiates an interactive 2-point calibration.
During the calibration process, you define the active area of the touch sensor by mapping
locations to an absolute X/Y coordinate system. You touch two
target areas
on the
sensor. Touching the target areas sends the X/Y coordinates for those touch points to the
controller. The controller calculates all other touch points based on these two points.
The Calibrate command sets the calibration targets (points) 12½ percent inward from the
corner of the video image. Setting the targets inward makes the calibration process easier
and more accurate.
