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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 Tomasz Malesinski
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "system.h"
#include "timer.h"
static long cycles_new = 0;
void TIMER1_ISR(void)
{
if (cycles_new > 0)
{
TIMER1.load = cycles_new - 1;
cycles_new = 0;
}
if (pfn_timer != NULL)
{
cycles_new = -1;
/* "lock" the variable, in case timer_set_period()
* is called within pfn_timer() */
pfn_timer();
cycles_new = 0;
}
TIMER1.clr = 1; /* clear the interrupt */
}
bool timer_set(long cycles, bool start)
{
if (start)
{
if (pfn_unregister != NULL)
{
pfn_unregister();
pfn_unregister = NULL;
}
TIMER1.ctrl &= ~0x80; /* disable the counter */
TIMER1.ctrl |= 0x40; /* reload after counting down to zero */
TIMER1.ctrl &= ~0xc; /* no prescaler */
TIMER1.clr = 1; /* clear an interrupt event */
}
if (start || (cycles_new == -1)) /* within isr, cycles_new is "locked" */
{ /* enable timer */
TIMER1.load = cycles - 1;
TIMER1.ctrl |= 0x80; /* enable the counter */
}
else
cycles_new = cycles;
return true;
}
bool timer_start(void)
{
irq_set_int_handler(IRQ_TIMER1, TIMER1_ISR);
irq_enable_int(IRQ_TIMER1);
return true;
}
void timer_stop(void)
{
TIMER1.ctrl &= ~0x80; /* disable timer 1 */
irq_disable_int(IRQ_TIMER1);
}
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