CCS C Compiler Manual PCB / PCM / PCH

PreProcessor
TICK=xx
Sets the desired time for 1 tick. xx can be used with ns(nanoseconds), us
(microseconds), ms (milliseconds), or s (seconds). If the desired tick time can't be
achieved it will set the time to closest achievable time and will generate a warning
specifying the exact tick time. The default value is 1us.
BITS=x
Sets the variable size used by the get_ticks() and set_ticks() functions for
returning and setting the tick time. x can be 8 for 8 bits, 16 for 16 bits or 32 for
32bits. The default is 32 for 32 bits.
ISR
Uses the timer's interrupt to increment the upper bits of the tick timer. This mode
requires the the global interrupt be enabled in the main program.
NOISR
The get_ticks() function increments the upper bits of the tick timer. This requires
that the get_ticks() function be called more often then the timer's overflow rate.
NOISR is the default mode of operation.
STREAM=id
Associates a stream identifier with the tick timer. The identifier may be used in
functions like get_ticks().
DEFINE=id
Creates a define named id which specifies the number of ticks that will occur in
one second. Default define name if not specified is TICKS_PER_SECOND.
Define name must start with an ASCII letter 'A' to 'Z', an ASCII letter 'a' to 'z' or an
ASCII underscore ('_').
COUNTER or COUNTER=x
Sets up specified timer as a counter instead of timer. x specifies the prescallar to
setup counter with, default is1 if x is not specified specified. The function
get_ticks() will return the current count and the function set_ticks() can be used to
set count to a specific starting value or to clear counter.
Purpose:
This directive creates a tick timer using one of the PIC's timers. The tick timer is
initialized to zero at program start. This directive also creates the define
TICKS_PER_SECOND as a floating point number, which specifies that number of
ticks that will occur in one second.
Examples:
#USE TIMER(TIMER=1,TICK=1ms,BITS=16,NOISR)
unsigned int16 tick_difference(unsigned int16 current, unsigned int16 previous) {
return(current - previous);
}
void main(void) {
unsigned int16 current_tick, previous_tick;
current_tick = previous_tick = get_ticks();
while(TRUE) {
current_tick = get_ticks();
if(tick_difference(current_tick, previous_tick) > 1000) {
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