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S5L8700: implement timer driver

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21801 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Bertrik Sikken 2009-07-12 10:44:02 +00:00
parent 8029bee2fe
commit 61394b725b
2 changed files with 106 additions and 0 deletions
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2
firmware/export/s5l8700.h
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@ -23,6 +23,8 @@
#define REG16_PTR_T volatile uint16_t *
#define REG32_PTR_T volatile uint32_t *
#define TIMER_FREQ 50000000L
/* 04. CALMADM2E */
/* Following registers are mapped on IO Area in data memory area of Calm. */

104
firmware/target/arm/s5l8700/timer-s5l8700.c Normal file
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@ -0,0 +1,104 @@
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2008 Rafaël Carré
*
* 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.
TODO: investigate why the timer seems to count twice as fast as expected
*/
void INT_TIMERD(void)
{
/* clear interrupt */
TDCON = TDCON;
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 */
TDCMD = (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 */
TDCON = (1 << 12) | /* TD_INT0_EN */
(cs << 8) | /* TS_CS */
(0 << 4); /* TD_MODE_SEL, 0 = interval mode */
TDPRE = prescale - 1;
TDDATA0 = count;
TDCMD = (1 << 0); /* TD_ENABLE */
/* enable interrupt */
INTMSK |= (1 << 9);
return true;
}
bool timer_start(void)
{
TDCMD = (1 << 0); /* TD_ENABLE */
return true;
}
void timer_stop(void)
{
TDCMD = (0 << 0); /* TD_ENABLE */
}