Clock library

The clock library is the interface between Contiki and the platform specific clock functionality.

The clock library defines a macro, CLOCK_SECOND, to convert seconds into the tick resolution of the platform. Typically this is 1-10 milliseconds, e.g. 4*CLOCK_SECOND could be 512. A 16 bit counter would thus overflow every 1-10 minutes. Platforms use the tick interrupt to maintain a long term count of seconds since startup.

Platforms may also implement rtimers for greater time resolution and for real-time interrupts, These use a corresponding RTIMER_SECOND.

Note

These timers do not necessarily have a common divisor or are phase locked. One may be crystal controlled and the other may not. Low power operation or sleep will often use one for wake and disable the other, then give it a tick correction after wakeup.

The clock library need in many cases not be used directly. Rather, the timer library, event timers, or rtimer library should be used.

See Also

Timer library

Event timers

Realtime library

Macros
#define	CLOCK_SECOND
	A second, measured in GCLK generator 5 clock source. More...

Functions
void	clock_delay (unsigned int delay)
void	clock_delay_usec (uint16_t dt)
	Delay a given number of microseconds. More...
unsigned short	clock_fine (void)
int	clock_fine_max (void)
	Deprecated platform-specific routines. More...
void	clock_init (void)
	Initialize the clock library. More...
CCIF unsigned long	clock_seconds (void)
	Get the current value of the platform seconds. More...
void	clock_set_seconds (unsigned long sec)
	Set the value of the platform seconds. More...
CCIF clock_time_t	clock_time (void)
	Get the current clock time. More...
void	clock_wait (clock_time_t t)
	Wait for a given number of ticks. More...

#define CLOCK_SECOND

A second, measured in GCLK generator 5 clock source.

Referenced by _TC3_Handler(), broadcast_rate_drop(), clock_adjust_ticks(), clock_irq_callback(), default_timebase(), duty_cycle(), echo_reply_callback(), handle_dao_timer(), handle_dio_timer(), if(), main(), new_dio_interval(), phase_wait(), PROCESS_THREAD(), rpl_reset_periodic_timer(), set_dao_lifetime_timer(), uaodv_request_route_to(), uip_ds6_addr_add(), uip_ds6_init(), uip_ds6_send_rs(), and while().

void clock_delay

(

unsigned int

delay

)

Referenced by leds_blink().

void clock_delay_usec

(

uint16_t

dt

)

Delay a given number of microseconds.

Parameters

dt	How many microseconds to delay.

Note

Interrupts could increase the delay by a variable amount.

unsigned short clock_fine

(

void

)

int clock_fine_max

(

void

)

Deprecated platform-specific routines.

void clock_init

(

void

)

Initialize the clock library.

This function initializes the clock library and should be called from the main() function of the system.

References clock_irq_callback(), tc_config::clock_prescaler, tc_config::clock_source, tc_16bit_config::compare_capture_channel, tc_config::counter_16_bit, GCLK_GENERATOR_5, tc_config::run_in_standby, TC_CALLBACK_CC_CHANNEL0, TC_CLOCK_PRESCALER_DIV1, tc_enable(), tc_enable_callback(), tc_get_config_defaults(), tc_init(), tc_instance, tc_register_callback(), TIMER, and TIMER_PERIOD.

Referenced by main().

CCIF unsigned long clock_seconds

(

void

)

Get the current value of the platform seconds.

This could be the number of seconds since startup, or since a standard epoch.

Returns

The value.

References seconds.

Referenced by print_stats(), stimer_elapsed(), stimer_expired(), stimer_remaining(), stimer_restart(), and stimer_set().

void clock_set_seconds

(

unsigned long

sec

)

Set the value of the platform seconds.

Parameters

sec	The value to set.

CCIF clock_time_t clock_time

(

void

)

Get the current clock time.

This function returns the current system clock time.

Returns

The current clock time, measured in system ticks.

References system_interrupt_enter_critical_section(), system_interrupt_leave_critical_section(), and ticks.

Referenced by double_interval(), echo_reply_callback(), fire(), if(), make_addrmap(), new_interval(), PROCESS_THREAD(), schedule_for_end(), timer_expired(), timer_remaining(), timer_restart(), timer_set(), and update_time().

void clock_wait

(

clock_time_t

t

)

Wait for a given number of ticks.

Parameters

t	How many ticks.