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/**
* TaskScheduler Test sketch - use of task IDs and watchdog timer to identify hung tasks
* Test case:
* Watchdog timer is set to 2 seconds (interrupt + reset)
* A hearbeat task (resetting the watchdog timer) is scheduled with 500 ms interval
* A number of tasks are running every 1 second and "rolling the dice" 0..19. If 5, task is made to enter infinite loop
* Device should reset in 2 seconds after a task enters infinite loop
* A task id and a control point number are saved to EEPROM prior to device reset, and are displayed after reboot.
* In real life, device might chose to NOT activate certain tasks which failed previously (failed sensors for instance)
*/
#define _TASK_SLEEP_ON_IDLE_RUN
#define _TASK_WDT_IDS
#include <TaskScheduler.h>
#include <EEPROM.h>
#include <avr/wdt.h>
Scheduler ts;
// Callback methods prototypes
void TaskCB();
void HB(); bool HBOn(); void HBOff();
// Three tasks emulating accidental infinite loop
Task tTask1(TASK_SECOND, TASK_FOREVER, &TaskCB, &ts, true);
Task tTask2(TASK_SECOND, TASK_FOREVER, &TaskCB, &ts, true);
Task tTask3(TASK_SECOND, TASK_FOREVER, &TaskCB, &ts, true);
// Heartbeat task - resetting the watchdog timer periodically
// Initiates WDT on enable, and deactivates it on disable
Task tHB(500, TASK_FOREVER, &HB, &ts, false, &HBOn, &HBOff);
/**
* Emulating task callback function
* Prints task id and randomly "hangs" in two places.
* Control points are stored on the task prior to section which might hang,
* making this information available to the WDT interrupt handler
*/
void TaskCB() {
Task& T = ts.currentTask();
Serial.print("Task #:");
Serial.print(T.getId());
Serial.print(" current iteration = ");
Serial.println(T.getRunCounter());
// Hang if random number between 0 and 19 is 5 (5% probability)
T.setControlPoint(10);
if (random(20) == 5) for(;;);
// Hang if random number between 0 and 99 is more that 95 (5% probability)
T.setControlPoint(95);
if (random(100) > 94) for(;;);
}
/**
* This On Enable method sets up the WDT
* for interrupt and reset after 2 seconds
*/
bool HBOn() {
//disable interrupts
cli();
//reset watchdog
wdt_reset();
//set up WDT interrupt
WDTCSR = (1<<WDCE)|(1<<WDE);
//Start watchdog timer with aDelay prescaller
WDTCSR = (1<<WDIE)|(1<<WDE)|(WDTO_2S & 0x2F);
// WDTCSR = (1<<WDIE)|(WDTO_2S & 0x2F); // interrupt only without reset
//Enable global interrupts
sei();
}
/**
* This On Disable method disables WDT
*/
void HBOff() {
wdt_disable();
}
/**
* This is a periodic reset of WDT
*/
void HB() {
wdt_reset();
}
/**
* Watchdog timeout ISR
*
*/
ISR(WDT_vect)
{
Task& T = ts.currentTask();
digitalWrite(13, HIGH);
EEPROM.write(0, (byte)T.getId());
EEPROM.write(1, (byte)T.getControlPoint());
digitalWrite(13, LOW);
}
/**
* Standard arduino setup routine
*/
void setup() {
Serial.begin(115200);
randomSeed(analogRead(0)+analogRead(5));
pinMode(13, OUTPUT);
digitalWrite(13, LOW);
Serial.println("WDT heartbeat test");
Serial.print("Last task before reset="); Serial.println(EEPROM.read(0));
Serial.print("Last control point before reset="); Serial.println(EEPROM.read(1));
delay(2000);
tHB.enableDelayed();
}
/**
* Not much is left for the loop()
*/
void loop() {
ts.execute();
}
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