File content as of revision 0:a046f7397436:

// C.P. Diduch
// EE4333 Robotics Lab-3, January 18, 2014.
// Template for implementation of a PI Speed Control System
#include "rtos.h"
#include "mbed.h"
// Function prototypes
void PiControllerISR(void);
void WdtFaultISR(void);
void ExtCollisionISR(void);
void PiControlThread(void const *argument);
void ExtCollisionThread(void const *argument);
void Watchdog(void const *n);
// Global variables for interrupt handler
int Position;
// Processes and threads
int32_t SignalPi, SignalWdt, SignalExtCollision;
osThreadId PiControl,WdtFault,ExtCollision;
osThreadDef(PiControlThread, osPriorityRealtime, DEFAULT_STACK_SIZE); // Declare Control as a thread/process
osThreadDef(ExtCollisionThread, osPriorityHigh, DEFAULT_STACK_SIZE); // Declare External Collision as a thread/process
osTimerDef(Wdtimer, Watchdog); // Declare a watch dog timer
// osPriorityIdle = -3, ///< priority: idle (lowest)
// osPriorityLow = -2, ///< priority: low
// osPriorityBelowNormal = -1, ///< priority: below normal
// osPriorityNormal = 0, ///< priority: normal (default)
// osPriorityAboveNormal = +1, ///< priority: above normal
// osPriorityHigh = +2, ///< priority: high
// osPriorityRealtime = +3, ///< priority: realtime (highest)
// IO Port Configuration
DigitalOut led1(LED1);
DigitalOut led2(LED2);
DigitalOut led3(LED3);
DigitalOut led4(LED4);
Serial pc(USBTX, USBRX); // Pins (tx, rx) for PC serial channel
Ticker PeriodicInt; // Declare a timer interrupt: PeriodicInt
InterruptIn Bumper(p8); // External interrupt pin declared as Bumper
// ******** Main Thread ********
int main() { // This thread executes first upon reset or power-on.
char x;
// Attach the address of the ExtCollisionISR to the rising edge of Bumper:
Bumper.rise(&ExtCollisionISR);
// Start execution of the threads: PiControlThread and ExtCollisionThread:
PiControl = osThreadCreate(osThread(PiControlThread), NULL);
ExtCollision = osThreadCreate(osThread(ExtCollisionThread), NULL);
// Start the watch dog timer and enable the watch dog interrupt
osTimerId OneShot = osTimerCreate(osTimer(Wdtimer), osTimerOnce, (void *)0);
pc.printf("\r\n RTOS Template Program");
// May prompt user for input data here:
// Specify address of the PeriodicInt ISR as PiControllerISR, specify the interval
// in seconds between interrupts, and start interrupt generation:
PeriodicInt.attach(&PiControllerISR, .05);
do {
 if (pc.readable()){
 x=pc.getc();
 pc.putc(x); // Echo keyboard entry
// Start or restart the watchdog timer interrupt and set to 2000ms.
 osTimerStart(OneShot, 2000);
 led3=0; // Clear watch dog led3 status
 led4=0;
 }
 // Display variables at the terminal emulator for logging:
 pc.printf("\r\n%6d", Position); // The terminal emulator may be configured to
 // store received data to a file
 Thread::wait(500); // Go to sleep for 500 ms
}
while(1);
}
// ******** Control Thread ********
void PiControlThread(void const *argument) {
while (true) {
 osSignalWait(SignalPi, osWaitForever); // Go to sleep until, SignalPi, is received.
 led2= !led2; // Alive status - led2 toggles each time PiControlThread is signaled.
 Position = Position + 1;
 }
}
// ******** Collision Thread ********
void ExtCollisionThread(void const *argument) {
while (true) {
 // Go to sleep until signal, SignalExtCollision, is received:
 osSignalWait(SignalExtCollision, osWaitForever);
 led4 = 1;
 }
}
// ******** Watchdog Interrupt Handler ********
void Watchdog(void const *n) {
 led3=1; // led3 is activated when the watchdog timer times out
}
// ******** Period Timer Interrupt Handler ********
void PiControllerISR(void) {
 // Activate the signal, PiControl, with each periodic timer interrupt.
 osSignalSet(PiControl,0x1); }

// ******** Collision Interrupt Handler ********
void ExtCollisionISR(void) {
 // Activate the signal, ExtCollision, with each pexternal interrupt.
 osSignalSet(ExtCollision,0x1);
 }