c5dedd7d76
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21559 a1c6a512-1295-4272-9138-f99709370657
130 lines
3.3 KiB
C
130 lines
3.3 KiB
C
/***************************************************************************
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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) 2007 by Michael Sevakis
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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 "cpu.h"
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#include "system.h"
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#include "timer.h"
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#include "logf.h"
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/* GPB0/TOUT0 should already have been configured as output so that pin
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should not be a functional pin and TIMER0 output unseen there */
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void TIMER0(void)
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{
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if (pfn_timer != NULL)
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pfn_timer();
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SRCPND = TIMER0_MASK;
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INTPND = TIMER0_MASK;
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}
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static void stop_timer(void)
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{
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/* mask interrupt */
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INTMSK |= TIMER0_MASK;
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/* stop any running TIMER0 */
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TCON &= ~(1 << 0);
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/* clear pending */
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SRCPND = TIMER0_MASK;
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INTPND = TIMER0_MASK;
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}
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bool timer_set(long cycles, bool start)
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{
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bool retval = false;
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/* Find the minimum factor that puts the counter in range 1-65535 */
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unsigned int prescaler = (cycles + 65534) / 65535;
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/* Maximum divider setting is x / 256 / 16 = x / 4096 - min divider
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is x / 2 however */
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if (prescaler <= 2048)
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{
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int oldlevel;
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unsigned int divider;
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if (start && pfn_unregister != NULL)
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{
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pfn_unregister();
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pfn_unregister = NULL;
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}
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oldlevel = disable_irq_save();
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TCMPB0 = 0;
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TCNTB0 = (unsigned int)cycles / prescaler;
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/* Max prescale is 255+1 */
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for (divider = 0; prescaler > 256; prescaler >>= 1, divider++);
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TCFG0 = (TCFG0 & ~0xff) | (prescaler - 1);
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TCFG1 = (TCFG1 & ~0xf) | divider;
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restore_irq(oldlevel);
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retval = true;
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}
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return retval;
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}
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bool timer_start(void)
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{
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bool retval = true;
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int oldstatus = disable_interrupt_save(IRQ_FIQ_STATUS);
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stop_timer();
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/* neurosis - make sure something didn't set GPB0 to TOUT0 */
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if ((GPBCON & 0x3) != 0x2)
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{
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/* manual update: on (to reset count) */
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TCON |= (1 << 1);
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/* dead zone: off, inverter: off, manual off */
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TCON &= ~((1 << 4) | (1 << 2) | (1 << 1));
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/* interval mode (auto reload): on */
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TCON |= (1 << 3);
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/* start timer */
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TCON |= (1 << 0);
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/* unmask interrupt */
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INTMSK &= ~TIMER0_MASK;
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}
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if (!(TCON & (1 << 0)))
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{
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/* timer could not be started due to config error */
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logf("Timer error: GPB0 set to TOUT0");
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retval = false;
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}
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restore_interrupt(oldstatus);
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return retval;
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}
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void timer_stop(void)
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{
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int oldstatus = disable_interrupt_save(IRQ_FIQ_STATUS);
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stop_timer();
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restore_interrupt(oldstatus);
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}
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