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
Small_Task();
Big_Task();
while(1);
}
void loop() {
delay(1000);
}
void Small_Task (void) {
Serial.println("......doing small task......");
for (int i = 0; i < 50000000; i++) { // dummy task
asm(" nop");
}
Serial.println("Small_Task finished refresh watchdog.");
wdt.RefreshWatchdog();
}
/* If Big_Task unable to reach #10, watchdog barks. */
void Big_Task (void) {
Serial.println("......doing big task, up to 10......");
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("Big_Task finished refresh watchdog.");
wdt.RefreshWatchdog();
}
void my_watchdog_irq_handler(uint32_t id) {
Serial.println("watchdog barks!!!");
wdt.StopWatchdog();
}
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
