wdt.c

以前做的一个仿PLC程序

/*****************************************************************************
 *   wdt.c:  Watchdog C file for NXP LPC17xx Family Microprocessors
 *
 *   Copyright(C) 2009, NXP Semiconductor
 *   All rights reserved.
 *
 *   History
 *   2009.05.27  ver 1.00    Prelimnary version, first Release
 *
*****************************************************************************/
#include "LPC17xx.h"

#define WDEN		0x00000001
#define WDRESET		0x00000002
#define WDTOF		0x00000004
#define WDINT		0x00000008

#define WDT_FEED_VALUE	0X00FF//0x003FFFFF

volatile uint32_t wdt_counter;

/*****************************************************************************
** Function name:		WDT_IRQHandler
**
** Descriptions:		Watchdog timer interrupt handler
**
** parameters:			None
** Returned value:		None
** 
*****************************************************************************/
void WDT_IRQHandler(void) 
{
  LPC_WDT->WDMOD &= ~WDTOF;		/* clear the time-out terrupt flag */
  wdt_counter++;
  return;
}

/*****************************************************************************
** Function name:		WDTInit
**
** Descriptions:		Initialize watchdog timer, install the
**				watchdog timer interrupt handler
**
** parameters:			None
** Returned value:		true or false, return false if the VIC table
**				is full and WDT interrupt handler can be
**				installed.
** 
*****************************************************************************/
void WDTInit( void )
{
  wdt_counter = 0;

  NVIC_EnableIRQ(WDT_IRQn);

  LPC_WDT->WDTC = WDT_FEED_VALUE;	/* once WDEN is set, the WDT will start after feeding */
  LPC_WDT->WDMOD = WDEN;

  LPC_WDT->WDFEED = 0xAA;		/* Feeding sequence */
  LPC_WDT->WDFEED = 0x55;    
//  return( TRUE );
}

/*****************************************************************************
** Function name:		WDTFeed
**
** Descriptions:		Feed watchdog timer to prevent it from timeout
**
** parameters:			None
** Returned value:		None
** 
*****************************************************************************/
void WDTFeed( void )
{
  LPC_WDT->WDFEED = 0xAA;		/* Feeding sequence */
  LPC_WDT->WDFEED = 0x55;
  return;
}

/******************************************************************************
**                            End Of File
******************************************************************************/