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Acquisition of coordinates
The coordinates of a position touched can be acquired. However, while the keypad is being
displayed, it is only possible to acquire a set of coordinates if an area outside the keypad is touched.
In this case the coordinates will be recorded together with the following coordinate status.
Coordinate status
When a set of coordinate is acquired, the steps performed, from when the pen (or user's finger)
touches the panel to when it is removed from the panel, can be tracked. The coordinate data acquired
this way also includes the status data, which is used to determine the pen-down position, pen-up
position, etc.
A problem may occur with the acquisition of the pen-up coordinates if the power is turned OFF or if
the application program clears the buffer while the pen is on the panel. In this case a status code
indicating that the pen-up coordinates cannot be acquired will be returned.
The following are the status values that can be obtained at the acquisition of coordinates. They are
defined in keypad.h.
KDC_DOWN If the touch panel is touched.
KDC_RUN If the pen is moved while it touches the panel (this status will be returned at
2.0 ms intervals if the pen remains still).
KDC_UP If the pen is removed from the panel.
KDC_CANCEL If the pen-down status can be returned but pen-down cannot be returned.
The following table contains the list of status values that the application may receive next time after
one piece of status information has been received.
This time
Down Run Up Cancel
Down X O O O
Run X O O O
Up O X X X
Previous
time
Cancel O X X X
O : Possibility to receive. X : No possibility to receive.
Resume-On process
The entire key buffer will be cleared if a resume-on boot is executed by turning the power off and
then on. However, if the power is turned off immediately after the key scan function sends a "data
present" reply, the data returned by the key scanning function will be returned if key input is
performed after the power has been turned on.