timer.h File Reference

Timer. More...

#include <stdint.h>

Macros
#define	TIMER_NS_PER_TICK   135
	Nanoseconds per timer tick. More...

Functions
uint32_t	timerGet ()
	Get current timer tick. More...
unsigned long	timerNsSince (uint32_t lastTick, uint32_t *storeCurrent)
	Calculate nanoseconds elapsed since a given tick. More...
uint32_t	timerSet (uint32_t count)
	Reset timer to count from specific tick. More...
void	timerSleepNs (unsigned long ns)
	Wait for a given number of nanoseconds. More...

Macro Definition Documentation

TIMER_NS_PER_TICK

#define TIMER_NS_PER_TICK   135

Nanoseconds per timer tick. Timer ticks once every 0.135uS.

Function Documentation

timerGet()

uint32_t timerGet

(

)

Get current timer tick.

Timer ticks every 0.135uS and overflows at 0xFFFFFFFF then carries on counting.

Returns

Current timer tick

timerNsSince()

unsigned long timerNsSince	(	uint32_t	lastTick,
		uint32_t *	storeCurrent
	)

Calculate nanoseconds elapsed since a given tick. Optionally store the current tick.

Useful for timeouts, or calculating time between frames.

Note

This function won't work correctly for periods longer than 579.82s due to timer overflow.

timerSet()

uint32_t timerSet

(

uint32_t

count

)

Reset timer to count from specific tick.

Note

There is a bug in the MMSP2 silicon which prevents starting the timer from 0, so this function will start it from 1 if you try to pass 0.

Parameters

count

Tick to start counting from

Returns

Tick the timer was at before being reset

timerSleepNs()

void timerSleepNs

(

unsigned long

ns

)

Wait for a given number of nanoseconds.

Note

This function won't work correctly if you try to wait for longer than 579.82s due to timer overflow.

Parameters

ns	Nanoseconds to wait