timer.c File Reference

Sets up and runs functions at given times. More...

#include "timer.h"
#include <unistd.h>

Functions
void	core_timer (int sig)
	The core timer. Determines whether or not it is time to run one of the functions that have timers attached to them. More...
void	initialise_core_timer (void)
	Begins an alarm which calls the "core_timer" function every 1ms * rate producing a calling frequency of 1kHz / rate.
int	OSWait (int n)
	Waits for 1 ms. More...
Timer	OSAttachTimer (int scale, void(*fct)(void))
	adds a function to a 1kHz/scale timer, ie. executes every 1ms*scale usage: OSAttachTimer(<scale>, &<function>); More...
int	OSDetachTimer (Timer handle)
	removes the Timer from the list More...
int	OSSetTime (int hrs, int mins, int secs)
	sets the system time More...
int	OSGetTime (int *hrs, int *mins, int *secs, int *ticks)
	Get system time (ticks in 1/100 sec) More...
int	OSShowTime (void)
	prints the time on the command line More...
int	OSGetCount (void)
	gives you the count in 1/100 sec since the system start More...

Variables
void(*	_functions [16])(void) = {NULL}
int	_function_timer_scales [16] = {0}
int	_timers_active = 0
int	_core_timedev = 1000
int	_clock_ticks = 0

Detailed Description

Sets up and runs functions at given times.

Author

Rhys Kessey

Marcus Pham (cleaned up)

These timer functions were written by Rhys Kessey The functions deal with two global variables, functions[] and function_timer_scales[] Every time a timer is linked to a function, values will be added to these arrays Every clock tick (determined by the rate that core_timer is called) these functions will be checked if the current clock tick is a multiple of a function scale, then the function will be executed. eg. functions[] = {f1,f2,f3,f4,NULL,NULL,NULL....} function_timer_scales[] = {1 ,2 ,1 ,4 ,0 ,0 ,0 ....} then every clock tick, f1 and f3 will be executed (in that order) every 2 clock ticks, f2 will be executed every 4 clock ticks, f4 will be executed

Function Documentation

void core_timer

(

int

sig

)

The core timer. Determines whether or not it is time to run one of the functions that have timers attached to them.

Parameters

sig	the signal

Timer OSAttachTimer	(	int	scale,
		void(*)(void)	fct
	)

adds a function to a 1kHz/scale timer, ie. executes every 1ms*scale usage: OSAttachTimer(<scale>, &<function>);

Parameters

scale	the rate to run the function
fct	the function to run, note must return void and have no arguments

Returns

the Timer struct for the timer

int OSDetachTimer

(

Timer

handle

)

removes the Timer from the list

Parameters

handle

the timer to remove

Returns

0 always

int OSGetCount

(

void

)

gives you the count in 1/100 sec since the system start

Returns

the count

int OSGetTime	(	int *	hrs,
		int *	mins,
		int *	secs,
		int *	ticks
	)

Get system time (ticks in 1/100 sec)

Parameters

hrs	the pointer to the hours integer
mins	the pointer to the mins integer
secs	the pointer to the secs integer
ticks	the pointer to the ticks integer

Returns

0 always

int OSSetTime	(	int	hrs,
		int	mins,
		int	secs
	)

sets the system time

Parameters

hrs	the hours
mins	the mins
secs	the secs

Returns

0 always

int OSShowTime

(

void

)

prints the time on the command line

Returns

0 always

int OSWait

(

int

n

)

Waits for 1 ms.

Parameters

n	the number of ms to wait for

Returns

0 always