65 lines
2 KiB
C
65 lines
2 KiB
C
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/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Bj<EFBFBD>rn Stenberg
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "config.h"
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#include "system.h"
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#include "kernel.h"
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#include "panic.h"
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void tick_start(unsigned int interval_in_ms)
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{
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unsigned long count;
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int prescale;
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count = CPU_FREQ/2 * interval_in_ms / 1000 / 16;
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if(count > 0x10000)
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{
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panicf("Error! The tick interval is too long (%d ms)\n",
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interval_in_ms);
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return;
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}
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prescale = cpu_frequency / CPU_FREQ;
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/* Note: The prescaler is later adjusted on-the-fly on CPU frequency
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changes within timer.c */
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/* We are using timer 0 */
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TRR0 = (unsigned short)(count - 1); /* The reference count */
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TCN0 = 0; /* reset the timer */
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TMR0 = 0x001d | ((unsigned short)(prescale - 1) << 8);
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/* restart, CLK/16, enabled, prescaler */
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TER0 = 0xff; /* Clear all events */
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ICR1 = 0x8c; /* Interrupt on level 3.0 */
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IMR &= ~0x200;
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}
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void TIMER0(void) __attribute__ ((interrupt_handler));
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void TIMER0(void)
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{
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/* Run through the list of tick tasks */
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call_tick_tasks();
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TER0 = 0xff; /* Clear all events */
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}
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