WATCHDOG.md

# WATCHDOG
## **Overview**
Provides watchdog APIs, such as setting the watchdog timeout duration and feeding a watchdog \(resetting a watchdog timer\).
If an error occurs in the main program of the system, for example, if the program crashes or the watchdog timer is not reset in time, the watchdog timer generates a reset signal, and the system restores from the suspending state to the normal state.
**Since:**
1.0
## **Summary**
## Files

File Name	Description
watchdog_if.h	Declares standard watchdog APIs.

## Enumerations

Enumeration Name	Description
WatchdogStatus { WATCHDOG_STOP, WATCHDOG_START }	Enumerates watchdog statuses.

## Functions

Function Name	Description
WatchdogOpen (int16_t wdtId)	struct DevHandle *  Opens a watchdog.
WatchdogClose (struct DevHandle *handle)	void  Closes a watchdog.
WatchdogGetStatus (struct DevHandle *handle, int32_t *status)	int32_t  Obtains the watchdog status.
WatchdogStart (struct DevHandle *handle)	int32_t  Starts a watchdog.
WatchdogStop (struct DevHandle *handle)	int32_t  Stops a watchdog.
WatchdogSetTimeout (struct DevHandle *handle, uint32_t seconds)	int32_t  Sets the watchdog timeout duration.
WatchdogGetTimeout (struct DevHandle *handle, uint32_t *seconds)	int32_t  Obtains the watchdog timeout duration.
WatchdogFeed (struct DevHandle *handle)	int32_t  Feeds a watchdog, that is, resets a watchdog timer.

## **Details**
## **Enumeration Type Documentation**
## WatchdogStatus
```
enum [WatchdogStatus](WATCHDOG.md#ga3c77a35e1051e3f99238029519ac1954)
```
**Description:**
Enumerates watchdog statuses.
To obtain the watchdog status, call the [WatchdogGetStatus](WATCHDOG.md#ga37d1311664523c25557b1280cb51ebdf) function.

Enumerator	Description
WATCHDOG_STOP	Stopped
WATCHDOG_START	Started

## **Function Documentation**
## WatchdogClose\(\)
```
void WatchdogClose (struct [DevHandle](DevHandle.md) * handle)
```
**Description:**
Closes a watchdog.
If you no longer need a watchdog, call this function to close it and release its device handle to prevent unnecessary use of memory resources.
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog device handle.

## WatchdogFeed\(\)
```
int32_t WatchdogFeed (struct [DevHandle](DevHandle.md) * handle)
```
**Description:**
Feeds a watchdog, that is, resets a watchdog timer.
After a watchdog is started, you must feed it to reset the watchdog timer periodically. If you do not do so, the watchdog hardware will reset the system upon a timeout.
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog handle, which is obtained via WatchdogOpen.

**Returns:**
Returns **0** if the watchdog is fed; returns a negative value otherwise.
## WatchdogGetStatus\(\)
```
int32_t WatchdogGetStatus (struct [DevHandle](DevHandle.md) * handle, int32_t * status )
```
**Description:**
Obtains the watchdog status.
For the available watchdog statuses, see [WatchdogStatus](WATCHDOG.md#ga3c77a35e1051e3f99238029519ac1954).
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog handle, which is obtained via WatchdogOpen.
status	Indicates the pointer to the watchdog status.

**Returns:**
Returns **0** if the watchdog status is obtained; returns a negative value otherwise.
## WatchdogGetTimeout\(\)
```
int32_t WatchdogGetTimeout (struct [DevHandle](DevHandle.md) * handle, uint32_t * seconds )
```
**Description:**
Obtains the watchdog timeout duration.
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog handle, which is obtained via WatchdogOpen.
seconds	Indicates the pointer to the timeout duration, in seconds.

**Returns:**
Returns **0** if the watchdog timeout duration is obtained; returns a negative value otherwise.
## WatchdogOpen\(\)
```
struct [DevHandle](DevHandle.md)* WatchdogOpen (int16_t wdtId)
```
**Description:**
Opens a watchdog.
Before operating a watchdog, you must call this function to open it and obtain its device handle.
**Parameters:**

Name	Description
wdtId	Indicates the watchdog ID.

**Returns:**
Returns the pointer to the device handle of the watch dog if the operation is successful; returns **NULL** otherwise.
## WatchdogSetTimeout\(\)
```
int32_t WatchdogSetTimeout (struct [DevHandle](DevHandle.md) * handle, uint32_t seconds )
```
**Description:**
Sets the watchdog timeout duration.
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog handle, which is obtained via WatchdogOpen.
seconds	Indicates the timeout duration, in seconds.

**Returns:**
Returns **0** if the setting is successful; returns a negative value otherwise.
## WatchdogStart\(\)
```
int32_t WatchdogStart (struct [DevHandle](DevHandle.md) * handle)
```
**Description:**
Starts a watchdog.
This function starts the watchdog timer. You must feed the watchdog periodically; otherwise, the watchdog hardware will reset the system upon a timeout.
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog handle, which is obtained via WatchdogOpen.

**Returns:**
Returns **0** if the watchdog is successfully started; returns a negative value otherwise.
**Attention:**
If the watchdog timer has started before this function is called, calling this function will succeed; however, the watchdog hardware determines whether to reset the timer.
## WatchdogStop\(\)
```
int32_t WatchdogStop (struct [DevHandle](DevHandle.md) * handle)
```
**Description:**
Stops a watchdog.
If the watchdog has stopped before this function is called, calling this function will succeed.
**Parameters:**

Name	Description
handle	Indicates the pointer to the watchdog handle, which is obtained via WatchdogOpen.

**Returns:**
Returns **0** if the watchdog is successfully stopped; returns a negative value otherwise.