WDT: Watchdog Timer

Overview

The MCUXpresso SDK provides a peripheral driver for the Watchdog Timer (WDT) module of MCUXpresso SDK devices.

Typical use case

Example use of WDT API.

void WDT_IRQHandler(void)
{
    wdt_int_flag = 1;

    if (wdt_int_cnt < 5)
    {
        WDT_ClearStatusFlags(DEMO_WDT_BASE);
        wdt_int_cnt++;
    }
    else
    {
        /* Wait for watchdog reset */
        while (1)
        {
        }
    }
}

int main(void)
{
    wdt_config_t config;

    BOARD_InitHardware();
    CLOCK_AttachClk(k32K_to_WDT_CLK);
    PRINTF("\r\nWatchdog example.\r\n");

    /* Check Reset source(First time device power on Watch dog reset source will be set) */
    if (kRESET_SrcWatchDog == RESET_GetResetSource())
    {
        PRINTF("Watchdog reset occurred\r\n");
    }
    /* Clear reset source */
    RESET_ClearResetSource();

    config.enableWdtReset = true;
    config.loadValue = WDT_CYCLE_NUM;

    WDT_Init(DEMO_WDT_BASE, &config);
    NVIC_EnableIRQ(WDT_IRQn);

    while (1)
    {
        if (wdt_int_cnt < 5)
        {
            PRINTF("Wait for watchdog interrupt\r\n");
        }
        else
        {
            PRINTF(
                "When next watchdog interrupt occurrs and the program will stay in the watchdog interrupt "
                "handler.\r\n");
            PRINTF("WDT will trigger watchdog reset after load_value(3s) * 2\r\n");
        }

        while (wdt_int_flag == 0)
        {
        }
        wdt_int_flag = 0;

        PRINTF("Watchdog interrupt occurred and interrupt is cleared in the watchdog interrupt handler\r\n");
    }
}

Files
file	fsl_wdt.h

Data Structures
struct	wdt_config_t
	Describes WDT configuration structure. More...

Functions
void	WDT_Init (WDT_Type *base, const wdt_config_t *config)
	Initializes the WDT with configuration. More...
void	WDT_Deinit (WDT_Type *base)
	Disable the WDT peripheral. More...
static void	WDT_Unlock (WDT_Type *base)
	Unlock WDT access. More...
static void	WDT_Lock (WDT_Type *base)
	Lock WDT access. More...
static void	WDT_ClearStatusFlags (WDT_Type *base)
	Clears status flags. More...
void	WDT_GetDefaultConfig (wdt_config_t *config)
	Initializes WDT configure sturcture. More...
static void	WDT_Refresh (WDT_Type *base, uint32_t cycle)
	Refresh WDT counter. More...

Driver version
#define	FSL_WDT_DRIVER_VERSION   (MAKE_VERSION(2, 0, 0))
	WDT driver version.

---

Data Structure Documentation

struct wdt_config_t

Data Fields
bool	enableWdtReset
	true: Watchdog timeout will cause a chip reset false: Watchdog timeout will not cause a chip reset
uint32_t	loadValue
	Load value, default value is 0xFFFFFFFF.

Function Documentation

void WDT_Init	(	WDT_Type *	base,
		const wdt_config_t *	config
	)

This function initializes the WDT.

Parameters

base	WDT peripheral base address.
config	pointer to configuration structure

void WDT_Deinit

(

WDT_Type *

base

)

This function shuts down the WDT.

Parameters

base	WDT peripheral base address.

static void WDT_Unlock ( WDT_Type *  base )

inlinestatic

This function unlock WDT access.

Parameters

base	WDT peripheral base address.

static void WDT_Lock ( WDT_Type *  base )

inlinestatic

This function unlock WDT access.

Parameters

base	WDT peripheral base address.

static void WDT_ClearStatusFlags ( WDT_Type *  base )

inlinestatic

This function clears WDT status flag.

Parameters

base	WDT peripheral base address.

void WDT_GetDefaultConfig

(

wdt_config_t *

config

)

This function initializes the WDT configure structure to default value. The default value are:

*   config->enableWdtReset = true;
*   config->loadValue = 0xffffffff;
* 

Parameters

config

pointer to WDT config structure

static void WDT_Refresh ( WDT_Type *  base, uint32_t  cycle  )

inlinestatic

This function feeds the WDT. This function should be called before WDT timer is in timeout.

Parameters

base	WDT peripheral base address.
cycle	time-out interval