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SEMAPHORES and TIMING
create_semaphore
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Function
To create a new semaphore.
Syntax
#include “unos.h”
unsigned int create_semaphore( void );
Remarks
May be called at any time to create a new semaphore. The semaphore created is initialised to
a value of 1 with a multiplier value of 1.
NOTE: When declaring a semaphore variable, ALWAYS initialize it to 0xFFFF. In this manner,
unintentioned operations on a semaphore which has not been created will be avoided, as the
UNOS semaphore functions will be able to detect the illegal semaphore number.
Parameters
None.
Return value
The created semaphore's number. If unsuccessful, 0xFFFF.
create_timer
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Function
To create a new timer.
Syntax
#include “unos.h”
timer_struc * create_timer( void );
Remarks
After allocating the required timer structure from the UNOS heap, the timer is inserted into the
inactive timer queue.
Parameters
None.
Return value
Pointer to the new timer data structure. This structure is defined in unos.h.
init_semaphore
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Function
To initialise a semaphore's variables.
Syntax
#include “unos.h”
void init_semaphore( unsigned int semaphore_number, unsigned int semaphore_value,
unsigned int multiplier_value);
Remarks
Sets the semaphore value and multiplier value of the nominated semaphore. (Multiplier value
is the number of signals on the semaphore generated by a single signal call on the
semaphore.)
Parameters
semaphore_number: The number by which the semaphore to be affected is known.
semaphore_value:
The new count value of the semaphore.
multiplier_value:
The new value of the semaphore's multiplier.
Return value
None.
reset_timer
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PC_UNOS Reference Manual
Page 41 of 56
$Revision:: 1.0$