14
Command Summary
4.5
GLT Model
Touch Screen
The GLT24064 facilitates user touch input in one of two distinct ways. Coordinate mode will report
events by supplying their exact position on the screen. Region mode will report events within defined
boundaries on the screen. Both modes are outlined below.
Coordinate Mode
In coordinate mode all touch events are reported using three
single byte values. First, the type of event is transmitted,
followed by the x and y coordinates of its position. Pressure
and drag thresholds must be exceeded for an event to be
registered. A low drag threshold will result in greater tracking
accuracy but transmits much more data to the host. Care
should be taken to find balance. This mode offers a great
degree of flexibility and creativity.
Table 11: Coordinate Mode Event Prefixes
Return Value
1
2
4
Touch Event
Press Release Drag
Region Mode
A simpler, keypad style alternative to coordinate mode,
region mode offers only a single byte for each touch event.
Unique regions are created by specifying a position, size, and
return values. A value corresponding to a specific region is
returned when an event occurs within its bounds. Events
outside of regions result in transmission of the value 255.
Regions can be deleted individually or collectively when no
longer needed. This mode allows quick and easy set up.
Table 12: Region Mode Event Responses
Return Value
Key Down Key Up
Key Down
255
Touch Event
Press
Release
Drag
Out of Region
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