File content as of revision 6:bd874c16ce2f:

#include "mbed.h"
#include "rtos.h"
#include "wdt.h"
// Sample program using the Watchdog
// ---------------------------------
//    * Three threads co-operate to flash two LEDs
//    * A simple way to inject a fault, by pressing a button
//    * The watchdog is configured with a 32ms timeout
#define ON 1
#define OFF 0
DigitalOut led_red(LED_RED, ON);
DigitalIn button(PTD0, PullUp);
DigitalOut led1(PTC12, OFF);
DigitalOut led2(PTC13, OFF);
Serial pc(USBTX, USBRX);
// This ticker is used to feed the watch dog
Ticker tick;
// Threads
Thread threadT(osPriorityNormal,1000); // timer thread
Thread threadLED1(osPriorityNormal,1000); // thread LED1
Thread threaddetection(osPriorityNormal,1000);
//define the state of watch dog
enum wState {Working, Stopped} ;
wState watchdogflag;
AnalogIn ainled1(A0); //LED1 ADC INPUT
float volt1,volt2;

// ------------Fault Injection Button-------------
//  Wait while the button is down
//     Use this to simulate a STUCK fault
// -----------------------------------------------
void waitButton()
{

    while (!button) {
        //pc.printf("stop watchdog");
        watchdogflag=Stopped;
    }
}
// ---Thread for controlling LED 1----------------
//   Turn LED1 on/off in response to signals
// -----------------------------------------------
void led1_thread()    // method to run in thread
{
    osEvent evt ;
    while (true) {
        evt = Thread::signal_wait(0x0); // wait for any signal
        if (evt.status == osEventSignal) {
            if (evt.value.signals & 0x01) {
                led1 = ON ;
            }
            if (evt.value.signals & 0x02) led1 = OFF ;
        }
    }
}
// ---Thread for controlling LED 2----------------
//   Turn LED2 on/off in response to signals
// -----------------------------------------------
void led2_thread()    // method to run in thread
{
    osEvent evt ;
    while (true) {
        evt = Thread::signal_wait(0x0); // wait for any signal
        if (evt.status == osEventSignal) {
            if (evt.value.signals & 0x01) {
                led2 = ON ;
            }
            if (evt.value.signals & 0x02) led2 = OFF ;
        }
        // waitButton() ; // POSSIBLE FAULT HERE
    }
}
// ---Thread for timing --------------------------
//   Send signals to the other threads
// -----------------------------------------------
void timer_thread()    // method to run in thread
{
    while (true) {
        Thread::wait(250) ;
        threadLED1.signal_set(0x1) ;//on
        Thread::wait(250) ;
        threadLED1.signal_set(0x2) ;//off
        // waitButton() ; // POSSIBLE FAULT HERE
    }
}
void detection_thread()
{
    int counter=0;
    while (1) {
        volt1 = ainled1;
        if (volt1>0.90) {
            led_red=0;
        } else {
            if(led1==1) {
                if ((volt1<0.1)) {
                    counter++;
                    if (counter>5) {
                        if(led_red==1)led_red=0;
                        counter =0;
                    }
                } else {
                    if (led_red==0)led_red=1;
                }
            }
        }
        waitButton(); // POSSIBLE FAULT HERE
    }
}
// -----------MAIN-------------------------------
//    Configure watchdog. Start threads.
//    Show start up with RED for 1sec
//    Remember the watchdog is running
//       - 1024ms to set it once
//       - then must feed it every 32ms
// ----------------------------------------------
void watchdog()
{
    if (watchdogflag==Working) {
        wdt_kick_all();
    }
}

int main(void)
{

    wdt_32ms() ; // initialise watchdog - 32ms timeout
    watchdogflag = Working;
    tick.attach_us(callback(&watchdog), 20000);

    // start threads
    threadT.start(&timer_thread) ; // start the timer thread
    threadLED1.start(&led1_thread) ; // start the LED1 control thread
    threaddetection.start(&detection_thread);

    // show start-up
    led_red = OFF;
    Thread::wait(1000) ;//1ms
    led_red = ON;

}