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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2009 Bertrik Sikken
*
* 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 "inttypes.h"
#include "s5l8700.h"
#include "system.h"
#include "timer.h"
/* Timer driver for the S5L8700
The S5L8700 timer resolution is only 16-bit. Larger counts are done by using
both the clock-select and the clock prescaler to bring the count down into
the range of the 16-bit counter.
*/
void INT_TIMERC(void)
{
/* clear interrupt */
TCCON = TCCON;
if (pfn_timer != NULL) {
pfn_timer();
}
}
bool timer_set(long cycles, bool start)
{
static const int cs_table[] = {1, 2, 4, 6};
int prescale, cs;
long count;
/* stop and clear timer */
TCCMD = (1 << 1); /* TD_CLR */
/* optionally unregister any previously registered timer user */
if (start) {
if (pfn_unregister != NULL) {
pfn_unregister();
pfn_unregister = NULL;
}
}
/* scale the count down with the clock select */
for (cs = 0; cs < 4; cs++) {
count = cycles >> cs_table[cs];
if ((count < 65536) || (cs == 3)) {
break;
}
}
/* scale the count down with the prescaler */
prescale = 1;
while (count >= 65536) {
count >>= 1;
prescale <<= 1;
}
/* configure timer */
TCCON = (1 << 12) | /* TD_INT0_EN */
(cs << 8) | /* TS_CS */
(0 << 4); /* TD_MODE_SEL, 0 = interval mode */
TCPRE = prescale - 1;
TCDATA0 = count;
TCCMD = (1 << 0); /* TD_ENABLE */
/* enable interrupt */
INTMSK |= INTMSK_TIMERC;
return true;
}
bool timer_start(void)
{
TCCMD = (1 << 0); /* TD_ENABLE */
return true;
}
void timer_stop(void)
{
TCCMD = (0 << 0); /* TD_ENABLE */
}
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