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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 by Rob Purchase
*
* 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 "cpu.h"
#include "system.h"
#include "timer.h"
#include "logf.h"
static const int prescale_shifts[] = {1, 2, 3, 4, 5, 10, 12};
bool timer_set(long cycles, bool start)
{
bool found = false;
int prescale_option = 0;
int actual_cycles = 0;
/* Use the first prescale that fits Timer4's 20-bit counter */
while (!found && prescale_option < 7)
{
actual_cycles = cycles >> prescale_shifts[prescale_option];
if (actual_cycles < 0x100000)
found = true;
else
prescale_option++;
}
if (!found)
return false;
/* Stop the timer and set new prescale & ref count */
TCFG(4) &= ~TCFG_EN;
TCFG(4) = prescale_option << TCFG_SEL;
TREF(4) = actual_cycles;
if (start && pfn_unregister != NULL)
{
pfn_unregister();
pfn_unregister = NULL;
}
return true;
}
bool timer_start(void)
{
int oldstatus = disable_interrupt_save(IRQ_STATUS);
TCFG(4) |= TCFG_CLEAR | TCFG_IEN | TCFG_EN;
restore_interrupt(oldstatus);
return true;
}
void timer_stop(void)
{
int oldstatus = disable_interrupt_save(IRQ_STATUS);
TCFG(4) &= ~TCFG_EN;
restore_interrupt(oldstatus);
}
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