Class WDT
WDT Class
Description
A class used for initializing, starting, stopping watchdog timer.
Syntax
class WDT
Members
| Public Constructors | |
| A public constructor should not be used as this class is intended to be a singleton class. Access member functions using the object instance named WDT. |
| Public Methods | |
| WDT:: InitWatchdog | Initializes the watchdog, include time setting, and mode register |
| WDT:: StartWatchdog | Start the watchdog counting |
| WDT:: StopWatchdog | Stop the watchdog counting |
| WDT:: RefreshWatchdog | Refresh the watchdog counting to prevent WDT timeout |
| WDT:: InitWatchdogIRQ | Switch the watchdog timer to interrupt mode and register a watchdog timer timeout interrupt handler |
WDT:: InitWatchdog
Description
Initializes the watchdog, include time setting, and mode register.
Syntax
void InitWatchdog(uint32_t timeout_ms);
Parameters
timeout_ms: the watch-dog timer timeout value in millisecond (ms). The default action after watchdog timer timeout is to reset the whole system.
Returns
The function returns nothing.
Example Code
Example: WatchdogTimer
/**
* This example describes how to use watchdog api.
* In this example, watchdog is setup to 5s timeout.
* Watchdog won't bark if we refresh it before timeout in smallTask.
* The timer is also reloaded after refresh.
* Otherwise, while running bigTask, watchdog will restart system in default or call callback function if registered.
*/
#include "wdt.h"
#define RUN_CALLBACK_IF_WATCHDOG_BARKS (0)
WDT wdt;
void setup() {
Serial.begin(115200);
wdt.InitWatchdog(5000); // setup 5s watchdog
#if RUN_CALLBACK_IF_WATCHDOG_BARKS
wdt.InitWatchdogIRQ(my_watchdog_irq_handler, 0);
#else
// system would restart in default when watchdog barks
#endif
wdt.StartWatchdog(); // enable watchdog timer
successfulTask();
failedTask();
while (1)
;
}
void loop() {
}
void successfulTask(void) {
Serial.println("......doing small task......");
for (int i = 0; i < 50000000; i++) // dummy task
asm(" nop");
Serial.println("refresh watchdog\r\n");
wdt.RefreshWatchdog();
}
/**
* Doing this task will lead to failed refresh the
* watchdog timer within the time limits of 5 seconds
*/
void failedTask(void) {
Serial.println("......doing big task......");
for (int i = 0; i < 10; i++) {
Serial.print("doing dummy task #");
Serial.println(i, DEC);
for (int j = 0; j < 50000000; j++) // dummy task
asm(" nop");
}
Serial.println("refresh watchdog\r\n");
wdt.RefreshWatchdog();
}
void my_watchdog_irq_handler(uint32_t id) {
printf("watchdog barks!!!\r\n");
WDG_Cmd(DISABLE);
}
Notes and Warnings
NA
WDT:: StartWatchdog
Description
Start the watchdog counting.
Syntax
void StartWatchdog(void);
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
Example Code
Example: WatchdogTimer
You may refer to the code in previous section of WDT::InitWatchdog.
Notes and Warnings
NA
WDT:: StopWatchdog
Description
Stop the watchdog counting.
Syntax
void StopWatchdog(void);
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
Example Code
Example: WatchdogTimer
You may refer to the code in previous section of WDT::InitWatchdog.
Notes and Warnings
NA
WDT:: RefreshWatchdog
Description
Refresh the watchdog counting to prevent WDT timeout.
Syntax
void RefreshWatchdog(void);
Parameters
The function requires no input parameter.
Returns
The function returns nothing.
Example Code
Example: WatchdogTimer
You may refer to the code in previous section of WDT::InitWatchdog.
Notes and Warnings
NA
WDT:: InitWatchdogIRQ
Description
Switch the watchdog timer to interrupt mode and register a watchdog timer timeout interrupt handler. The interrupt handler will be called when the watchdog timer is timeout.
Syntax
void WDT::InitWatchdogIRQ(wdt_irq_handler handler, uint32_t id)
Parameters
handler: the callback function for WDT timeout interrupt.
id: the parameter for the callback function
Returns
The function returns nothing.
Example Code
Example: WatchdogTimer
You may refer to the code in previous section of WDT::InitWatchdog.
Notes and Warnings
NA
