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/****************************************************************************
* arch/arm/src/kinetis/kinetis_wdog.c
* arch/arm/src/chip/kinetis_wdog.c
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <arch/irq.h>
#include "up_arch.h"
#include "kinetis_internal.h"
#include "kinetis_wdog.h"
/****************************************************************************
* Private Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: kinetis_wdunlock
*
* Description:
* Watchdog timer unlock routine. Writing 0xc520 followed by 0xd928 will
* unlock the write once registers in the WDOG so they are writable
* within the WCT period.
*
****************************************************************************/
static void kinetis_wdunlock(void)
{
irqstate_t flags;
/* This sequence must execute within 20 clock cycles. Disable interrupts
* to assure that the following steps are atomic.
*/
flags = irqsave();
/* Write 0xC520 followed by 0xD928 to the unlock register */
putreg16(0xc520, KINETIS_WDOG_UNLOCK);
putreg16(0xd928, KINETIS_WDOG_UNLOCK);
irqrestore(flags);
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: kinetis_wddisable
*
* Description:
* Disable the watchdog timer
*
****************************************************************************/
void kinetis_wddisable(void)
{
uint16_t regval;
/* Unlock the watchdog so that we can write to registers */
kinetis_wdunlock();
/* Clear the WDOGEN bit to disable the watchdog */
regval = getreg16(KINETIS_WDOG_STCTRLH);
regval &= ~WDOG_STCTRLH_WDOGEN;
putreg16(regval, KINETIS_WDOG_STCTRLH);
}
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