User`s manual

PK2100
System Development s 4-3
Full C-Language Programming
Full C-language programming may access all the features available in
Dynamic C and its libraries. Gate programming and costatements use
Z-Worlds virtual driver. Full Dynamic C programming, of course, may
include any method or combinations of methods.
Virtual Driver
The virtual driver is a software package activated by a periodic interrupt
every 25 milliseconds and provides certain services to the application
programmer.
The virtual driver provides the following services.
 Running real-time second and millisecond clocks.
 Scanning the universal inputs to compare them against preset thresh-
olds.
 Scanning the digital inputs and setting digital outputs.
 Providing any number of virtual watchdog timers.
 Providing clock drive for the optional real-time kernel.
 Providing control for an audible beeper.
 Providing a driver for the keypad.
 Providing a driver for the liquid crystal display.
The following switches turn off the services of the virtual driver. If used,
they must precede driver calls. Leave the switch undefined to avoid
disabling the service.
 #define NOUNIVERSAL
Disable the virtual driver for digital inputs, universal inputs, digital
outputs and relays.
 #define NOTIMERS
Disable the virtual timers. The virtual timers are software timers,
useful in ladder logic programming and gate programming.
 #define NOLCD
Disable the liquid crystal display (LCD). This directive will prevent
the initialization of the LCD. Commands to the LCD have no effect
unless the LCD has been initialized.