Specifications

Touch Controllers Reference Guide38
Filter Number
Note:
MicroTouch provides this command for compatibility with older touchscreen
controllers. To ensure compatibility with all existing and future MicroTouch controllers,
do not use this command when developing your touch drivers and applications.
Syntax: <SOH>FNnn<CR>
where:
nn = Two ASCII characters ranging from 10 to 99.
Description: Sets the number of X, Y values that the controller uses to generate an
accurate coordinate after the touchscreen receives an initial touch.
You want to be sure a user’s finger makes full contact with the
touchscreen before the controller sends any data coordinates to the
host system.
For example, FN20 causes the controller to use the first 20 samples in
determining a touch location.
Note:
Very quick touches are always captured and sent to the host
system regardless of the filter number. For example, if a quick touch
generates only 5 samples, the controller still sends a coordinate to the
host system.
You need to change the filter value when system noise or a high
sensitivity setting causes erroneous input when the screen is first
touched. Specifically, you may need to make adjustments in the
following situations:
For button-selection applications
The host system sometimes receives the wrong button selection.
The host system does not properly recognize a button if the
button is touched on an outer edge.