watchdog.c

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/*
 * @brief WWDT example
 *
 * @note
 * Copyright(C) NXP Semiconductors, 2012
 * All rights reserved.
 *
 * @par
 * Software that is described herein is for illustrative purposes only
 * which provides customers with programming information regarding the
 * LPC products.  This software is supplied "AS IS" without any warranties of
 * any kind, and NXP Semiconductors and its licensor disclaim any and
 * all warranties, express or implied, including all implied warranties of
 * merchantability, fitness for a particular purpose and non-infringement of
 * intellectual property rights.  NXP Semiconductors assumes no responsibility
 * or liability for the use of the software, conveys no license or rights under any
 * patent, copyright, mask work right, or any other intellectual property rights in
 * or to any products. NXP Semiconductors reserves the right to make changes
 * in the software without notification. NXP Semiconductors also makes no
 * representation or warranty that such application will be suitable for the
 * specified use without further testing or modification.
 *
 * @par
 * Permission to use, copy, modify, and distribute this software and its
 * documentation is hereby granted, under NXP Semiconductors' and its
 * licensor's relevant copyrights in the software, without fee, provided that it
 * is used in conjunction with NXP Semiconductors microcontrollers.  This
 * copyright, permission, and disclaimer notice must appear in all copies of
 * this code.
 */

#include "board.h"

/*****************************************************************************
 * Private types/enumerations/variables
 ****************************************************************************/
#define FEED_ON_SYSTICKINT      0
#define FEED_ON_WARNINT         1
#define NO_FEED                 2

static volatile int wdtFeedState;
static volatile bool On = false;

/*****************************************************************************
 * Public types/enumerations/variables
 ****************************************************************************/

/*****************************************************************************
 * Private functions
 ****************************************************************************/

/* WDT interrupt handler */
static void wdt_handle(void) {
 uint32_t wdtStatus = Chip_WWDT_GetStatus(LPC_WWDT);

 On = (bool) !On;

 /* The chip will reset before this happens, but if the WDT doesn't
    have WWDT_MOD_WDRESET enabled, this will hit once */
 if (wdtStatus & WWDT_WDMOD_WDTOF) {
  /* A watchdog feed didn't occur prior to window timeout */
  Chip_WWDT_ClearStatusFlag(LPC_WWDT, WWDT_WDMOD_WDTOF);

  if (wdtFeedState == NO_FEED) {
   Chip_WWDT_Start(LPC_WWDT); /* Needs restart */
  }
 }
#if !defined(CHIP_LPC175X_6X)
 /* Handle warning interrupt */
 if (wdtStatus & WWDT_WDMOD_WDINT) {
  /* A watchdog feed didn't occur prior to warning timeout */
  Chip_WWDT_ClearStatusFlag(LPC_WWDT, WWDT_WDMOD_WDINT);

  if (wdtFeedState == FEED_ON_WARNINT) {
   Chip_WWDT_Feed(LPC_WWDT);
  }
 }
#endif 
}

/*****************************************************************************
 * Public functions
 ****************************************************************************/

void WDT_IRQHandler(void)
{
 wdt_handle();
}

void SysTick_Handler(void)
{
 if (wdtFeedState == FEED_ON_SYSTICKINT) {
  On = (bool) !On;
  Chip_WWDT_Feed(LPC_WWDT);
 }
}

int main(void)
{
 uint8_t ch;
 uint32_t wdtFreq;

 Board_Init();

 /* Watchdog will be fed on each watchdog interrupt */
 wdtFeedState = FEED_ON_SYSTICKINT;

 /* Initialize WWDT and event router */
 Chip_WWDT_Init(LPC_WWDT);

#if defined(WATCHDOG_CLKSEL_SUPPORT)
 Chip_WWDT_SelClockSource(LPC_WWDT, WWDT_CLKSRC_WATCHDOG_PCLK);
 wdtFreq = Chip_Clock_GetPeripheralClockRate(SYSCTL_PCLK_WDT) / 4;
#else
 wdtFreq = WDT_OSC;
#endif
 
 /* Set watchdog feed time constant to 0.1s */
 Chip_WWDT_SetTimeOut(LPC_WWDT, wdtFreq / 10);
#if !defined(CHIP_LPC175X_6X) 
 /* Set watchdog warning time to 512 ticks after feed time constant
    Set watchdog window time to 0.9s */
 Chip_WWDT_SetWarning(LPC_WWDT, 512);
 Chip_WWDT_SetWindow(LPC_WWDT, wdtFreq - (wdtFreq / 10));
#endif 
 /* Configure WWDT to reset on timeout */
 Chip_WWDT_SetOption(LPC_WWDT, WWDT_WDMOD_WDRESET);

 /* Clear watchdog warning and timeout interrupts */
 Chip_WWDT_ClearStatusFlag(LPC_WWDT, WWDT_WDMOD_WDTOF | WWDT_WDMOD_WDINT);

 /* Start watchdog */
 Chip_WWDT_Start(LPC_WWDT);

 /* Setup Systick for a 20Hz tick rate. Systick clock is clocked at
    CPU core clock speed */
 SysTick_Config(Chip_Clock_GetSystemClockRate() / 20);

 /* Enable watchdog interrupt */
 NVIC_ClearPendingIRQ(WDT_IRQn);
 NVIC_EnableIRQ(WDT_IRQn);

 /* Watchdog test options */
 DEBUGOUT("Press '1' to enable watchdog feed on systick interrupt\n\r");
#if !defined(CHIP_LPC175X_6X) 
 DEBUGOUT("Press '2' to enable watchdog feed on warning interrupt\n\r");
#endif 
 DEBUGOUT("Press '3' to disable watchdog feed (will reset device)\n\r");

 while (1) {
  do {
   ch = DEBUGIN();
   Board_LED_Set(0, On);
  } while ((ch < '1') || (ch > '4'));

  switch (ch) {
  case '1':
  default:
   wdtFeedState = FEED_ON_SYSTICKINT;
   DEBUGOUT("Watchdog feed on systick interrupt\r\n");
   break;
#if !defined(CHIP_LPC175X_6X)
  case '2':
   wdtFeedState = FEED_ON_WARNINT;
   DEBUGOUT("Watchdog feed on warning interrupt\r\n");
   break;
#endif
  case '3':
   wdtFeedState = NO_FEED;
   DEBUGOUT("No feeding - board will reset\r\n");
   break;
  }
 }
}