WATCHDOG

The WATCHDOG driver provides API for safety diagnostic which can detect a runaway CPU and generate either a reset or NMI (non-maskable interrupt) response. It generates resets or NMIs after a programmable period, or if no correct key sequence was written to the RTIWDKEY register.

Features Supported 

Supports Watchdog interrupt mode.

Supports digital windowed Watchdog feature.

SysConfig Features 

Note

It is strongly recommend to use SysConfig where it is available instead of using direct SW API calls. This will help simplify the SW application and also catch common mistakes early in the development cycle.

Selection of Watchdog instances.
Option to select Watchdog Window size.
Option to select Watchdog expiry time in millisecond.

Features NOT Supported 

Important Usage Guidelines 

Important Usage Guildelines

Example Usage 

Include the below file to access the APIs

Include 

#include <drivers/watchdog.h>

Instance Open Example 

    Watchdog_Params      params;

    Watchdog_paramsInit(&params);
    params.resetMode  = Watchdog_RESET_ON;
    gWatchdogHandle = Watchdog_open(CONFIG_WDT0, &params);
    if (!gWatchdogHandle) {
        DebugP_assert(FALSE);
    }

Instance Close Example 

    Watchdog_close(gWatchdogHandle);

Watchdog Service Example 

    Watchdog_clear(gWatchdogHandle);

Migration Guide 11.01 to 11.02 - AM62A 

Note

This section highlights API changes from 11.01 to 11.02 SDK for AM62A.

Return type change for Watchdog_setReaction and Watchdog_setWindowSize 

Watchdog_setReaction and Watchdog_setWindowSize return type changed from void to int32_t.
Both functions now return SystemP_SUCCESS on success, SystemP_FAILURE if handle is NULL.
Update callers to handle the return value.

Migration Guide 11.02 to 12.00 

Note

This section highlights API changes from 11.02 to 12.00 SDK.

Return type change for Watchdog_setReaction and Watchdog_setWindowSize 

Watchdog_setReaction and Watchdog_setWindowSize return type changed from void to int32_t.
Both functions now return SystemP_SUCCESS on success, SystemP_FAILURE if handle is NULL.
Update callers to handle the return value.

Examples and Demos 

See Watchdog interrupt mode

API Reference 

This file contains the prototype of WDT driver APIs.

Defines

WATCHDOG_CLEAR_STATUS: macro to clear the status.

Typedefs

typedef struct Watchdog_Config_s *Watchdog_Handle: Watchdog Handle.

typedef void (*Watchdog_Callback)(Watchdog_Handle handle, void *callbackFxnArgs)

Watchdog callback pointer.

This is the typedef for the function pointer that will allow a callback function to be specified in the Watchdog_Params structure. The function will take Watchdog_Handle of the Watchdog and user argument as arguments.

Enums

enum Watchdog_DebugMode

Watchdog debug stall settings.

This enumeration defines the debug stall modes for the Watchdog. On some targets, the Watchdog timer will continue to count down while a debugging session is halted. To avoid unwanted resets, the Watchdog can be set to stall while the processor is stopped by the debugger.

Values:

enumerator Watchdog_DEBUG_STALL_ON: Watchdog will be stalled at breakpoints

enumerator Watchdog_DEBUG_STALL_OFF: Watchdog will keep running at breakpoints

enum Watchdog_ResetMode

Watchdog reset mode settings.

This enumeration defines the reset modes for the Watchdog. The Watchdog can be configured to either generate a reset upon timeout or simply produce a periodic interrupt.

Values:

enumerator Watchdog_RESET_OFF: Timeouts generate NMI interrupt only

enumerator Watchdog_RESET_ON: Generates reset after timeout

enum Watchdog_WindowSize

Watchdog Window Size settings.

This enumeration defines the size of the digital watchdog window size.

Values:

enumerator Watchdog_WINDOW_100_PERCENT: Window size is 100%

enumerator Watchdog_WINDOW_50_PERCENT: Window size is 50%

enumerator Watchdog_WINDOW_25_PERCENT: Window size is 25%

enumerator Watchdog_WINDOW_12_5_PERCENT: Window size is 12.5%

enumerator Watchdog_WINDOW_6_25_PERCENT: Window size is 6.25%

enumerator Watchdog_WINDOW_3_125_PERCENT: Window size is 3.125%

enum Watchdog_DriverState

Watchdog Driver Status.

The enumeration describes the status of the Watchdog Driver Instance

Values:

enumerator Watchdog_DriverState_UNINIT: Driver is uninitialized.

enumerator Watchdog_DriverState_OPERATIONAL: Driver is operational.

Functions

void Watchdog_setReaction(Watchdog_Handle handle, uint32_t dwwdReaction)

Set DWWD reaction.

Note

DWWD need to be serviced if Reaction is changed when DWWD is enabled and Window is Open,to take immediate effect. If not serviced, DWWD will generated previously configured Reaction irrespective of current configuration.
If DWWD is enabled and Window is Close then any change in Reaction will take immediate effect. DWWD need not to be serviced in this case.

Parameters:

handle – Watchdog Handle
dwwdReaction – DWWD reaction for violation/expiration. Values given by macro

uint32_t Watchdog_getWindowSize(Watchdog_Handle handle)

Get DWWD Window Size.

Parameters:: handle – Watchdog Handle
Returns:: Watchdog Window size.

void Watchdog_setWindowSize(Watchdog_Handle handle, uint32_t dwwdWindowSize)

Set DWWD Window Size.

Note

DWWD need to be serviced if Window Size is changed when DWWD is enabled and Window is Open,to take immediate effect. If not serviced, DWWD Window Size will not be changed irrespective of current configuration.
If DWWD is enabled and Window is Close then any change in Window Size will take immediate effect. DWWD need not to be serviced in this case.

Parameters:

handle – Watchdog Handle
dwwdWindowSize – DWWD Window Size. Values given by macro

bool Watchdog_isClosedWindow(Watchdog_Handle handle)

The function checks for Closed Window.

Parameters:: handle – Watchdog Handle
Returns:: closed window status.

void Watchdog_clear(Watchdog_Handle handle)

The function clears the Watchdog to prevent a reset signal from being generated if the module is in Watchdog_RESET_ON reset mode.

Parameters:: handle – Watchdog Handle

void Watchdog_close(Watchdog_Handle handle)

The function closes a Watchdog peripheral specified by the Watchdog handle. It stops (holds) the Watchdog counting on applicable platforms.

Parameters:: handle – Watchdog Handle

void Watchdog_init(void): The functions initializes the Watchdog module.

void Watchdog_deinit(void): The functions de-initializes the Watchdog module.

Watchdog_Handle Watchdog_open(uint8_t index, Watchdog_Params *params)

Opens a Watchdog object with the index and parameters specified, and returns a Watchdog_Handle.

Parameters:

index – Logical peripheral number for the Watchdog indexed into the Watchdog_Config table
params – Pointer to an parameter block, if NULL it will use default values.

Returns:

A Watchdog_Handle on success or a NULL on an error or if it has been opened already.

void Watchdog_paramsInit(Watchdog_Params *params)

Function to set default values of Watchdog_Params in params.

Parameters:: params – [IN] pointer to the structure to be initialized

struct Watchdog_HwAttrs

#include <watchdog_rti.h>

Watchdog Driver HW configuration.

The structure is used to store the hardware specific configuration which is passed to each driver instance

Public Members

uint8_t instance: Instance of the Watchdog to be used.

uintptr_t baseAddr: Base address of the Watchdog address space to be used.

uint32_t wdtClkFrequency: WDT clock frequency.

struct Watchdog_Params

#include <watchdog_rti.h>

Watchdog Parameters.

Watchdog parameters are used with the Watchdog_open() call. Default values for these parameters are set using Watchdog_Params_init().

Public Members

Watchdog_Callback callbackFxn: Pointer to callback. Valid when resetMode = Watchdog_RESET_OFF.

void *callbackFxnArgs: User argument for callback function

Watchdog_ResetMode resetMode: Mode to enable resets.

Watchdog_DebugMode debugStallMode: Mode to stall watchdog at breakpoints.

Watchdog_WindowSize windowSize: Windowed watchdog window size.

uint32_t expirationTime: Expiration time in millisecond (ms).

struct Watchdog_Config

#include <watchdog_rti.h>

Watchdog Global configuration.

The Watchdog_Config structure contains a set of pointers used to characterize the Watchdog driver implementation.

This structure needs to be defined before calling Watchdog_init() and it must not be changed thereafter.