2541302089
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16895 a1c6a512-1295-4272-9138-f99709370657
78 lines
2.2 KiB
C
78 lines
2.2 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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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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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 "timer.h"
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#include "thread.h"
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extern void (*tick_funcs[MAX_NUM_TICK_TASKS])(void);
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void tick_start(unsigned int interval_in_ms)
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{
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/*
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* Based on default PCLK of 49.1568MHz - scaling chosen to give
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* remainder-free result for tick interval of 10ms (100Hz)
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* Timer input clock frequency =
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* fPCLK / {prescaler value+1} / {divider value}
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* TIMER_FREQ = 49156800 / 2
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* 13300 = TIMER_FREQ / 231 / 8
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* 49156800 = 19*(11)*(7)*7*5*5*(3)*2*2*2*2*2*2
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* 231 = 11*7*3
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*/
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/* stop timer 4 */
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TCON &= ~(1 << 20);
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/* Set the count for timer 4 */
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TCNTB4 = (TIMER_FREQ / 231 / 8) * interval_in_ms / 1000;
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/* Set the the prescaler value for timers 2,3, and 4 */
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TCFG0 = (TCFG0 & ~0xff00) | ((231-1) << 8);
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/* MUX4 = 1/16 */
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TCFG1 = (TCFG1 & ~0xff0000) | 0x030000;
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/* set manual bit */
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TCON |= 1 << 21;
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/* reset manual bit */
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TCON &= ~(1 << 21);
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/* interval mode */
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TCON |= 1 << 22;
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/* start timer 4 */
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TCON |= (1 << 20);
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/* timer 4 unmask interrupts */
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INTMSK &= ~TIMER4_MASK;
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}
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void TIMER4(void)
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{
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int i;
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/* Run through the list of tick tasks */
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for(i = 0; i < MAX_NUM_TICK_TASKS; i++)
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{
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if(tick_funcs[i])
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{
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tick_funcs[i]();
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}
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}
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current_tick++;
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SRCPND = TIMER4_MASK;
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INTPND = TIMER4_MASK;
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}
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