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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2007 by Michael Sevakis
*
* 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"
/* GPB0/TOUT0 should already have been configured as output so that pin
should not be a functional pin and TIMER0 output unseen there */
void TIMER0(void)
{
if (pfn_timer != NULL)
pfn_timer();
SRCPND = TIMER0_MASK;
INTPND = TIMER0_MASK;
}
static void stop_timer(void)
{
/* mask interrupt */
INTMSK |= TIMER0_MASK;
/* stop any running TIMER0 */
TCON &= ~(1 << 0);
/* clear pending */
SRCPND = TIMER0_MASK;
INTPND = TIMER0_MASK;
}
bool timer_set(long cycles, bool start)
{
bool retval = false;
/* Find the minimum factor that puts the counter in range 1-65535 */
unsigned int prescaler = (cycles + 65534) / 65535;
/* Maximum divider setting is x / 256 / 16 = x / 4096 - min divider
is x / 2 however */
if (prescaler <= 2048)
{
int oldlevel;
unsigned int divider;
if (start && pfn_unregister != NULL)
{
pfn_unregister();
pfn_unregister = NULL;
}
oldlevel = disable_irq_save();
TCMPB0 = 0;
TCNTB0 = (unsigned int)cycles / prescaler;
/* Max prescale is 255+1 */
for (divider = 0; prescaler > 256; prescaler >>= 1, divider++);
TCFG0 = (TCFG0 & ~0xff) | (prescaler - 1);
TCFG1 = (TCFG1 & ~0xf) | divider;
restore_irq(oldlevel);
retval = true;
}
return retval;
}
bool timer_start(void)
{
bool retval = true;
int oldstatus = disable_interrupt_save(IRQ_FIQ_STATUS);
stop_timer();
/* neurosis - make sure something didn't set GPB0 to TOUT0 */
if ((GPBCON & 0x3) != 0x2)
{
/* manual update: on (to reset count) */
TCON |= (1 << 1);
/* dead zone: off, inverter: off, manual off */
TCON &= ~((1 << 4) | (1 << 2) | (1 << 1));
/* interval mode (auto reload): on */
TCON |= (1 << 3);
/* start timer */
TCON |= (1 << 0);
/* unmask interrupt */
INTMSK &= ~TIMER0_MASK;
}
if (!(TCON & (1 << 0)))
{
/* timer could not be started due to config error */
logf("Timer error: GPB0 set to TOUT0");
retval = false;
}
restore_interrupt(oldstatus);
return retval;
}
void timer_stop(void)
{
int oldstatus = disable_interrupt_save(IRQ_FIQ_STATUS);
stop_timer();
restore_interrupt(oldstatus);
}
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