Watchdog Timer (WDT)

Driver for the WDT (Watchdog Timer).

This driver provides access to the main features of the WDT controller. The Watchdog Timer can be used to prevent system lock-up if the software becomes trapped in a deadlock. It features a 12-bit down counter that allows a watchdog period of up to 16 seconds (slow clock at 32.768 kHz). It can generate a general reset or a processor reset only. In addition, it can be stopped while the processor is in debug mode or idle mode.

Macros
#define	WDT_KEY_PASSWORD   0xA5000000
#define	WDT_MAX_VALUE   4095
#define	WDT_SLCK_DIV   128

Functions
void	wdt_disable (Wdt *p_wdt)
	Disable the watchdog timer. More...
uint32_t	wdt_get_status (Wdt *p_wdt)
	Check the watchdog timer status. More...
uint32_t	wdt_get_timeout_value (uint32_t ul_us, uint32_t ul_sclk)
	Get counter value or permitted range value of watchdog timer from the desired timeout period (in us). More...
uint32_t	wdt_get_us_timeout_period (Wdt *p_wdt, uint32_t ul_sclk)
	Get the timeout period of the WatchDog Timer in microseconds. More...
void	wdt_init (Wdt *p_wdt, uint32_t ul_mode, uint16_t us_counter, uint16_t us_delta)
	Initialize watchdog timer with the given mode. More...
void	wdt_restart (Wdt *p_wdt)
	Restart the watchdog timer. More...

#define WDT_KEY_PASSWORD   0xA5000000

Referenced by wdt_restart().

#define WDT_MAX_VALUE   4095

Referenced by wdt_get_timeout_value().

#define WDT_SLCK_DIV   128

Referenced by wdt_get_timeout_value(), and wdt_get_us_timeout_period().

void wdt_disable

(

Wdt *

p_wdt

)

Disable the watchdog timer.

uint32_t wdt_get_status

(

Wdt *

p_wdt

)

Check the watchdog timer status.

Returns

Bitmask of watchdog timer status.

uint32_t wdt_get_timeout_value	(	uint32_t	ul_us,
		uint32_t	ul_sclk
	)

Get counter value or permitted range value of watchdog timer from the desired timeout period (in us).

Note

The value returned by this function can be used by wdt_init() if it is not WDT_INVALID_ARGUMENT.

Parameters

ul_us	The desired timeout period (in us).
ul_sclk	The slow clock on board (in Hz).

Returns

If the desired period is beyond the watchdog period, this function returns WDT_INVALID_ARGUMENT. Otherwise it returns valid value.

References max, min, WDT_INVALID_ARGUMENT, WDT_MAX_VALUE, and WDT_SLCK_DIV.

uint32_t wdt_get_us_timeout_period	(	Wdt *	p_wdt,
		uint32_t	ul_sclk
	)

Get the timeout period of the WatchDog Timer in microseconds.

Parameters

p_wdt	Pointer to a WDT instance.
ul_sclk	The slow clock frequency (in Hz).

Returns

The timeout period in microseconds.

References WDT_SLCK_DIV.

void wdt_init	(	Wdt *	p_wdt,
		uint32_t	ul_mode,
		uint16_t	us_counter,
		uint16_t	us_delta
	)

Initialize watchdog timer with the given mode.

Parameters

p_wdt	Pointer to a WDT instance.
ul_mode	Bitmask of watchdog timer mode.
us_counter	The value loaded in the 12-bit Watchdog Counter.
us_delta	The permitted range for reloading the Watchdog Timer.

void wdt_restart

(

Wdt *

p_wdt

)

Restart the watchdog timer.

References WDT_KEY_PASSWORD.