WDT: Watchdog Timer

Overview

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

Typical use case

Example use of WDT API. Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/wdt

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

Enumerations
enum	_wdt_flags {   kWDT_TimeoutFlag = WDT_WDMOD_TOF_MASK,   kWDT_InterruptFlag = WDT_WDMOD_INT_MASK }
	Describes WDT flags. More...

Driver version
#define	FSL_WDT_DRIVER_VERSION   (MAKE_VERSION(2, 0, 1))
	Defines WDT driver version 2.0.1. More...

WDT Initialization and De-initialization
void	WDT_GetDefaultConfig (wdt_config_t *config)
	Initializes the WDT configuration structure. More...
void	WDT_Init (WDT_Type *base, const wdt_config_t *config)
	Initializes the WDT. More...
void	WDT_Deinit (WDT_Type *base)
	Shuts down the WDT. More...

WDT Functional Operation
static void	WDT_Enable (WDT_Type *base)
	Enables the WDT module. More...
static uint32_t	WDT_GetStatusFlags (WDT_Type *base)
	Gets the WDT all status flags. More...
static void	WDT_ClearStatusFlags (WDT_Type *base, uint32_t mask)
	Clears the WDT flag. More...
static void	WDT_SetTimeoutCounter (WDT_Type *base, uint32_t timeoutCount)
	Sets the WDT timeout counter. More...
static void	WDT_Feed (WDT_Type *base)
	Feed WDT timer. More...
static uint32_t	WDT_GetCurrentCount (WDT_Type *base)
	Get the current value of WDT. More...

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Data Structure Documentation

struct wdt_config_t

Data Fields
uint32_t	timeoutCounter
	Timeout counter for WDT, should be between 0xFF ~ 0x7FFFFF, indicates timeoutValue between (TWDCLK * 256 * 4) and (TWDCLK * 224 * 4), TWDCLK = 1/WDT_CLK. More...
bool	enableReset
	WDT reset enable, when enable, WDT timeout causes a chip reset. More...
bool	enableWdog
	Enables or disables WDT. More...

Field Documentation

uint32_t wdt_config_t::timeoutCounter

bool wdt_config_t::enableReset

bool wdt_config_t::enableWdog

Macro Definition Documentation

#define FSL_WDT_DRIVER_VERSION   (MAKE_VERSION(2, 0, 1))

Enumeration Type Documentation

enum _wdt_flags

Enumerator
kWDT_TimeoutFlag	WDT timeout flag, set when WDT times out.
kWDT_InterruptFlag	WDT interrupt flag, set in interrupt mode, indicates WDT interrupt due to WDT counter-underflow happens.

Function Documentation

void WDT_GetDefaultConfig

(

wdt_config_t *

config

)

This function initializes the WDT configuration structure to default values. The default values are as follows.

*   wdtConfig->timeoutValue = 0xFFFFU;
*   wdtConfig->enableReset = true;
*   wdtConfig->enableWdog = true;
* 

Parameters

config

Pointer to the WDT configuration structure.

See Also

wdt_config_t

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

This function initializes the WDT. When called, the WDT runs according to the configuration.

This is an example.

*   wdt_config_t config;
*   WDT_GetDefaultConfig(&config);
*   config.timeoutValue = 0x7ffU;
*   WDT_Init(wdt_base,&config);
* 

Parameters

base	WDT peripheral base address
config	The configuration of WDT

void WDT_Deinit

(

WDT_Type *

base

)

This function shuts down the WDT.

static void WDT_Enable ( WDT_Type *  base )

inlinestatic

Parameters

base	WDT peripheral base address

static uint32_t WDT_GetStatusFlags ( WDT_Type *  base )

inlinestatic

This function gets all status flags.

This is an example for getting the Running Flag.

*   uint32_t status;
*   status = WDT_GetStatusFlags (wdt_base) & kWDT_TimeoutFlag;
* 

Parameters

base	WDT peripheral base address

Returns

State of the status flag: asserted (true) or not-asserted (false).

See Also

_wdt_flags

• true: a related status flag has been set.
• false: a related status flag is not set.

static void WDT_ClearStatusFlags ( WDT_Type *  base, uint32_t  mask  )

inlinestatic

This function clears the WDT status flag.

This is an example for clearing the timeout (interrupt) flag.

*   WDT_ClearStatusFlags(wdt_base,kWDT_TimeoutFlag);
* 

Parameters

base	WDT peripheral base address
mask	The status flags to clear, only support clear kWDT_TimeoutFlag.

static void WDT_SetTimeoutCounter ( WDT_Type *  base, uint32_t  timeoutCount  )

inlinestatic

This function sets the timeout counter. The timeoutCount should be between 0xFF ~ 0x7FFFFF, writing values below 0xFF cause 0x0000 00FF to be loaded to the WDT timer counter. The minimum timeoutValue is (TWDCLK * 256 * 4) and the maximum value is (TWDCLK * 224 * 4), TWDCLK = 1/WDT_CLK.

Parameters

base	WDT peripheral base address
timeoutCount	WDT timeout counter; count of WDT clock tick.

static void WDT_Feed ( WDT_Type *  base )

inlinestatic

This is a mandatory step, if this function isn't called after enabling the WDT, WDT will ignore timeout errors and will not generate a WDT interrupt or reset the chip.

Parameters

base	WDT peripheral base address

static uint32_t WDT_GetCurrentCount ( WDT_Type *  base )

inlinestatic

The value reported by this function is older than the actual one. Retrieving this value takes up to 6 watchdog clock cycles + 6 system clock cycles due to the lock and synchronization procedure.

Parameters

base	WDT peripheral base address

Returns

Current value of WDT