Carrol Touch TouchSystems CarrollTouch Prog, Руководство программиста

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CARROLL TOUCH Chapter 7 - CTKERN
Touch System Programmer’s Guide 7-9
Methods for Interfacing CTKERN and an Application
Program
Application programs generally use either an interrupt mode or a
polling mode to retrieve touch information.
Polling Mode
Using the polling mode, the application program periodically checks
the touch state using GetTouchState (1). If the application does this at
a comparatively rapid rate, touch state information is current. If the
application polls at a slower rate, there is danger of missing transitions
in the touch state during the time between polls.
Interrupt Mode
In the interrupt mode, the application program installs a CTKERN user
event handler (UEH) using SetUserEventHandler (7). Whenever the
touch state changes, CTKERN places the touch state parameters in the
CPU registers and calls the application’s UEH. The application’s UEH
then reads the parameters from the registers and copies them into
variables within the application. The application program should keep
the CTKERN UEH as short as possible, as touch information may be
lost if the screen is touched while the hardware interrupts are turned off.
If the CTKERN UEH is disabled for a period of time then re-enabled,
touch state changes that occurred while the UEH was disabled are lost.
Loading the CTKERN Driver
Command Line
The CTKERN driver command line has the following syntax:
ctkern options
The available
options
follow.
U
= Uninstalls the driver.
Tn
= TAPI software interrupt.
n
may be any unused software
interrupt. The default is 55H.
Kn
= CTKERN software interrupt.
n
may be any unused
software interrupt. The default is 56H.