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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 Jens Arnold
*
* 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 <stdlib.h>
#include "config.h"
#include "system.h"
#include "cpu.h"
#include "timer.h"
static int base_prescale;
void TIMER1(void) __attribute__ ((interrupt_handler));
void TIMER1(void)
{
if (pfn_timer != NULL)
pfn_timer();
TER1 = 0xff; /* clear all events */
}
bool timer_set(long cycles, bool start)
{
int phi = 0; /* bits for the prescaler */
int prescale = 1;
while (cycles > 0x10000)
{
prescale <<= 1;
cycles >>= 1;
}
if (prescale > 4096/CPUFREQ_MAX_MULT)
return false;
if (prescale > 256/CPUFREQ_MAX_MULT)
{
phi = 0x05; /* prescale sysclk/16, timer enabled */
prescale >>= 4;
}
else
phi = 0x03; /* prescale sysclk, timer enabled */
base_prescale = prescale;
prescale *= (cpu_frequency / CPU_FREQ);
if (start)
{
if (pfn_unregister != NULL)
{
pfn_unregister();
pfn_unregister = NULL;
}
phi &= ~1; /* timer disabled at start */
/* If it is already enabled, writing a 0 to the RST bit will clear
the register, so we clear RST explicitly before writing the real
data. */
TMR1 = 0;
}
/* We are using timer 1 */
TMR1 = 0x0018 | (unsigned short)phi | ((unsigned short)(prescale - 1) << 8);
TRR1 = (unsigned short)(cycles - 1);
if (start || (TCN1 >= TRR1))
TCN1 = 0; /* reset the timer */
TER1 = 0xff; /* clear all events */
return true;
}
bool timer_start(void)
{
ICR2 = 0x90; /* interrupt on level 4.0 */
and_l(~(1<<10), &IMR);
TMR1 |= 1; /* start timer */
return true;
}
void timer_stop(void)
{
TMR1 = 0; /* disable timer 1 */
or_l((1<<10), &IMR); /* disable interrupt */
}
void timers_adjust_prescale(int multiplier, bool enable_irq)
{
/* tick timer */
TMR0 = (TMR0 & 0x00ef)
| ((unsigned short)(multiplier - 1) << 8)
| (enable_irq ? 0x10 : 0);
if (pfn_timer)
{
/* user timer */
int prescale = base_prescale * multiplier;
TMR1 = (TMR1 & 0x00ef)
| ((unsigned short)(prescale - 1) << 8)
| (enable_irq ? 0x10 : 0);
}
}
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