WDT Interface

Driver API for WDT (plib_wdt.h) More...

Typedefs
typedef void(*	WDT_CALLBACK_HANDLER) (uint32_t status)
	Function pointer type for the Watchdog Timer fault callback.

Functions
void	WDT_Configure (uint16_t wdv, uint16_t wdd, uint32_t mode)
	Configures the Watchdog Timer (WDT). Programs the WDT Mode Register with the specified watchdog counter value, window value, and configuration options.
void	WDT_Restart (void)
	Restarts the Watchdog Timer. Reloads the WDT counter by writing WDT_CR with the correct password key. This function can be called at any time to kick the watchdog.
void	WDT_SetCallbackHandler (WDT_CALLBACK_HANDLER callback)
	Registers the callback handler to be invoked from the WDT ISR.
uint32_t	WDT_StatusGet (void)
	Reads and returns the Watchdog Status Register (WDT_SR). Performs a single read of WDT_SR and returns the raw value. Test the result with WDT_SR_WDUNF_Msk (underflow) and WDT_SR_WDERR_Msk (error). Reading WDT_SR clears both the WDUNF and WDERR flags.
bool	WDT_IsEnabled (void)
	Checks if the WDT is enabled.

Description

Driver API for WDT (plib_wdt.h)

Usage Example

The following example demonstrates typical usage of the WDT peripheral:

 
#include "plib_wdt.h"
#include <stdint.h>
#include <stdbool.h>
 
volatile bool wdt_underflow_triggered = false;
volatile bool wdt_error_triggered     = false;
 
static void WDT_FaultCallback(uint32_t status)
{
    if ((status & WDT_SR_WDUNF_Msk) != 0U)
    {
        wdt_underflow_triggered = true;
        //user operation (e.g., log error, safe shutdown)
    }
 
    if ((status & WDT_SR_WDERR_Msk) != 0U)
    {
        wdt_error_triggered = true;
        //user operation (e.g., log error, safe shutdown)
    }
}
 
int32_t configure_wdt(void)
{
    
    /* WDV/WDD are 12-bit fields (0x000-0xFFF) of WDT_MR. */
    const uint16_t wdt_timeout_period_value = 0x800U;   
    const uint16_t wdt_window_period_value  = 0x400U;   
 
    /* Register callback handler for WDT fault */
    WDT_SetCallbackHandler(&WDT_FaultCallback);
 
    /* Configure WDT with all settings in one call (write-once register)
     * - Timeout period : WDV = 0x800 (~8 seconds at 32.768 kHz SLCK)
     * - Window period  : WDD = 0x400
     * - Reset on fault : enabled
     * - Fault interrupt: enabled
     * - Idle halt      : disabled (keep running in idle)
     * - Debug halt     : enabled (stop during debug)
     */
    WDT_Configure(wdt_timeout_period_value, wdt_window_period_value,
        WDT_MR_WDRSTEN_Msk | WDT_MR_WDFIEN_Msk | WDT_MR_WDDBGHLT_Msk);
 
    return 0;
}
 

Typedef Documentation

WDT_CALLBACK_HANDLER

typedef void(* WDT_CALLBACK_HANDLER) (uint32_t status)

Function pointer type for the Watchdog Timer fault callback.

Parameters

status

Snapshot of WDT_SR captured once by WDT_Handler(). Test it with the status masks: WDT_SR_WDUNF_Msk : Watchdog Underflow occurred. WDT_SR_WDERR_Msk : Watchdog Error (out-of-window reload) occurred.

Function Documentation

WDT_Configure()

void WDT_Configure	(	uint16_t	wdv,
		uint16_t	wdd,
		uint32_t	mode )

Configures the Watchdog Timer (WDT). Programs the WDT Mode Register with the specified watchdog counter value, window value, and configuration options.

Note

The WDT_MR register is write-once after a processor reset. Writing WDT_MR also reloads and restarts the down counter, so the watchdog begins counting immediately when this function is called.

Parameters

wdv	Watchdog counter value (12-bit). Valid range: 0x000 to 0xFFF. Values outside this range are silently truncated to the low 12 bits.
wdd	Watchdog delta/window value (12-bit). Valid range: 0x000 to 0xFFF. Values outside this range are silently truncated to the low 12 bits. Programming wdd >= wdv disables the reload-window check, allowing WDT_Restart() to be called anywhere within [0, wdv] (non-windowed mode).
mode	Bitwise OR of WDT_MR_WDDIS_Msk (disable watchdog), WDT_MR_WDRSTEN_Msk (reset on fault), WDT_MR_WDFIEN_Msk (fault interrupt), WDT_MR_WDIDLEHLT_Msk (halt in idle/sleep), and/or WDT_MR_WDDBGHLT_Msk (halt in debug).

Returns

void

WDT_IsEnabled()

bool WDT_IsEnabled

(

void

)

Checks if the WDT is enabled.

Returns

true if the WDT is enabled (WDDIS = 0), false if disabled.

WDT_Restart()

void WDT_Restart

(

void

)

Restarts the Watchdog Timer. Reloads the WDT counter by writing WDT_CR with the correct password key. This function can be called at any time to kick the watchdog.

Returns

void

WDT_SetCallbackHandler()

void WDT_SetCallbackHandler

(

WDT_CALLBACK_HANDLER

callback

)

Registers the callback handler to be invoked from the WDT ISR.

Parameters

callback

Pointer to the callback function. This function sets a user-defined function that will be called when a WDT fault (underflow or error) interrupt occurs. The callback receives the WDT_SR status value as an argument.

Returns

void

WDT_StatusGet()

uint32_t WDT_StatusGet

(

void

)

Reads and returns the Watchdog Status Register (WDT_SR). Performs a single read of WDT_SR and returns the raw value. Test the result with WDT_SR_WDUNF_Msk (underflow) and WDT_SR_WDERR_Msk (error). Reading WDT_SR clears both the WDUNF and WDERR flags.

Returns

The WDT_SR register value at the time of the read.