136 lines
2.6 KiB
C
136 lines
2.6 KiB
C
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#include "sys/clock.h"
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#include "sys/etimer.h"
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#include <avr/io.h>
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#include <avr/interrupt.h>
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static volatile clock_time_t count;
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/*---------------------------------------------------------------------------*/
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SIGNAL(SIG_OUTPUT_COMPARE0)
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{
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++count;
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if(etimer_pending()) {
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etimer_request_poll();
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}
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}
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/* External clock source does not work ? */
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#if 0
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void
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clock_init(void)
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{
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cli ();
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TIMSK &= ((unsigned char)~(1 << (TOIE0)));
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TIMSK &= ((unsigned char)~(1 << (OCIE0)));
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/* Disable TC0 interrupt */
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/**
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* set Timer/Counter0 to be asynchronous
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* from the CPU clock with a second external
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* clock(32,768kHz)driving it
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*/
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ASSR |= (1 << (AS0));
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TCCR0 = _BV (CS02) | _BV (CS01) | _BV (WGM1);
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TCNT0 = 0;
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OCR0 = 128;
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TIMSK |= (1 << (OCIE0));
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TIMSK |= (1 << (TOIE0));
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sei ();
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}
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#endif
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/*---------------------------------------------------------------------------*/
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void
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clock_init(void)
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{
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cli ();
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/* Select internal clock */
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ASSR = 0x00;
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/* Set counter to zero */
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TCNT0 = 0;
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/*
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* Set comparison register:
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* Crystal freq. is 16000000,
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* pre-scale factor is 1024, i.e. we have 125 "ticks" / sec:
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* 16000000 = 1024 * 125 * 125
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*/
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OCR0 = 125;
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/*
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* Set timer control register:
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* - prescale: 1024 (CS00 - CS02)
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* - counter reset via comparison register (WGM01)
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*/
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TCCR0 = _BV(CS00) | _BV(CS01) | _BV(CS02) | _BV(WGM01);
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/* Clear interrupt flag register */
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TIFR = 0x00;
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/*
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* Raise interrupt when value in OCR0 is reached. Note that the
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* counter value in TCNT0 is cleared automatically.
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*/
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TIMSK = _BV (OCIE0);
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/*
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* Counts the number of ticks. Since clock_time_t is an unsigned
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* 16 bit data type, time intervals of up to 524 seconds can be
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* measured.
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*/
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count = 0;
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sei ();
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}
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/*---------------------------------------------------------------------------*/
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clock_time_t
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clock_time(void)
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{
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return count;
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}
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/*---------------------------------------------------------------------------*/
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/**
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* Delay the CPU for a multiple of TODO
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*/
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void
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clock_delay(unsigned int i)
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{
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for (; i > 0; i--) { /* Needs fixing XXX */
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unsigned j;
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for (j = 50; j > 0; j--)
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asm volatile("nop");
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}
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}
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/*---------------------------------------------------------------------------*/
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/**
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* Wait for a multiple of 1 / 125 sec = 0.008 ms.
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*
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*/
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void
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clock_wait(int i)
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{
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clock_time_t start;
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start = clock_time();
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while(clock_time() - start < (clock_time_t)i);
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}
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/*---------------------------------------------------------------------------*/
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void
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clock_set_seconds(unsigned long sec)
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{
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// TODO
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}
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unsigned long
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clock_seconds(void)
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{
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return count / CLOCK_SECOND;
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}
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