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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Björn Stenberg
*
* 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 "config.h"
#include "system.h"
#include "kernel.h"
#include "panic.h"
void tick_start(unsigned int interval_in_ms)
{
unsigned long count;
int prescale;
count = CPU_FREQ/2 * interval_in_ms / 1000 / 16;
if(count > 0x10000)
{
panicf("Error! The tick interval is too long (%d ms)\n",
interval_in_ms);
return;
}
prescale = cpu_frequency / CPU_FREQ;
/* Note: The prescaler is later adjusted on-the-fly on CPU frequency
changes within timer.c */
/* We are using timer 0 */
TRR0 = (unsigned short)(count - 1); /* The reference count */
TCN0 = 0; /* reset the timer */
TMR0 = 0x001d | ((unsigned short)(prescale - 1) << 8);
/* restart, CLK/16, enabled, prescaler */
TER0 = 0xff; /* Clear all events */
ICR1 = 0x8c; /* Interrupt on level 3.0 */
IMR &= ~0x200;
}
void TIMER0(void) __attribute__ ((interrupt_handler));
void TIMER0(void)
{
/* Run through the list of tick tasks */
call_tick_tasks();
TER0 = 0xff; /* Clear all events */
}
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