contiki/cpu/avr/dev/clock.c

#include "sys/clock.h"
#include "dev/clock-avr.h"
#include "sys/etimer.h"

#include <avr/io.h>
#include <avr/interrupt.h>

static volatile clock_time_t count, scount;
static volatile unsigned long seconds;

/*---------------------------------------------------------------------------*/
//SIGNAL(SIG_OUTPUT_COMPARE0)
ISR(AVR_OUTPUT_COMPARE_INT)
{
  count++;
  if(++scount == CLOCK_SECOND) {
    scount = 0;
    seconds++;
  }
  if(etimer_pending()) {
    etimer_request_poll();
  }
}

/* External clock source does not work ? */
#if 0
void
clock_init(void)
{
  cli ();
  TIMSK &= ((unsigned char)~(1 << (TOIE0)));
  TIMSK &= ((unsigned char)~(1 << (OCIE0)));
  /* Disable TC0 interrupt */

  /** 
   *  set Timer/Counter0 to be asynchronous 
   *  from the CPU clock with a second external 
   *  clock(32,768kHz)driving it
   */
  ASSR |= (1 << (AS0));
  TCCR0 = _BV (CS02) | _BV (CS01) | _BV (WGM1);

  TCNT0 = 0;
  OCR0 = 128;
  
  TIMSK |= (1 << (OCIE0));
  TIMSK |= (1 << (TOIE0));
  sei ();
}
#endif

/*---------------------------------------------------------------------------*/
void
clock_init(void)
{
  cli ();


  OCRSetup();

  /*
   * Counts the number of ticks. Since clock_time_t is an unsigned
   * 16 bit data type, time intervals of up to 524 seconds can be
   * measured.
   */
  scount = count = 0;

  sei ();
}

/*---------------------------------------------------------------------------*/
clock_time_t
clock_time(void)
{
  clock_time_t tmp;
  do {
    tmp = count;
  } while(tmp != count);
  return tmp;
}
/*---------------------------------------------------------------------------*/
/**
 * Delay the CPU for a multiple of TODO
 */
void
clock_delay(unsigned int i)
{
  for (; i > 0; i--) {		/* Needs fixing XXX */
    unsigned j;
    for (j = 50; j > 0; j--)
      asm volatile("nop");
  }
}

/*---------------------------------------------------------------------------*/
/**
 * Wait for a multiple of 1 / 125 sec = 0.008 ms.
 *
 */
void
clock_wait(int i)
{
  clock_time_t start;

  start = clock_time();
  while(clock_time() - start < (clock_time_t)i);
}
/*---------------------------------------------------------------------------*/
void
clock_set_seconds(unsigned long sec)
{
    // TODO
}

unsigned long
clock_seconds(void)
{
  unsigned long tmp;
  do {
    tmp = seconds;
  } while(tmp != seconds);
  return tmp;
}