timer.h File Reference

The timer module provides an event interface to the hardware timers. More...

#include <stdint.h>

Go to the source code of this file.

Typedefs
typedef struct ALARM	ALARM
	ALARM type.
typedef void(*	alarmcallback_t )(void)
	Type for alarm callback functions.
Functions
int8_t	sb_timer_cancelAlarm (ALARM *alrm)
	Cancel an alarm.
ALARM *	sb_timer_setAlarm (alarmcallback_t callback, uint16_t alarmtime, uint16_t cycle)
	Create a new alarm.
int8_t	sb_timer_delay (uint16_t waittime)
	waits for a specific number of ms
void	sb_timer_delay_abort ()
	Aborts an active sb_timer_delay.

---

Detailed Description

The timer module provides an event interface to the hardware timers.

Version:

$Rev: 149 $

The module uses the 16-bit timer 1 of the ATmega32. The timer is dynamically configured as needed by the registered alarms and should always be clocked as slow as possible to keep the interrupt load low. When no alarms are registered, the timer clock is disabled.

The timer module uses dynamic memory management (malloc/free) for the allocation of the ALARM types.

---

Typedef Documentation

typedef void(* alarmcallback_t)(void)

Type for alarm callback functions.

Alarm callback functions are invoked on the interrupt level whenever the associated alarm expires. The programming model for callback functions is similar to that of interrupt service routines.

---

Function Documentation

int8_t sb_timer_cancelAlarm

(

ALARM *

alrm

)

Cancel an alarm.

Parameters:

alrm

identifier of the alarm that should be canceled

Returns:

0 on success, -1 if an error occurred.

int8_t sb_timer_delay

(

uint16_t

waittime

)

waits for a specific number of ms

This function must not be invoked with interrupts disabled, i.e. from an interrupt handler (or generally, from the ISR level) or a critical section of the application.

Parameters:

waittime

wait time in ms

Returns:

0 on success, negative value if a error occurred.

Return values:

	0	success
	-1	alarm could not be activated
	-2	sb_timer_delay invoked while interrupts disabled

void sb_timer_delay_abort

(

)

Aborts an active sb_timer_delay.

This function must be invoked on the ISR level.

ALARM* sb_timer_setAlarm	(	alarmcallback_t	callback,
		uint16_t	alarmtime,
		uint16_t	cycle
	)

Create a new alarm.

Parameters:

	callback	callback function that will be invoked whenever the alarm expires
	alarmtime	time in ms relative to the current time when the alarm shall expire the first time
	cycle	cycle time in ms for alarms that periodically expire after the first regular expiry

Returns:

the identifier of the alarm, or NULL if creating the alarm failed.