127 lines
5.2 KiB
C++
127 lines
5.2 KiB
C++
#include <avr/interrupt.h>
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#include <avr/io.h>
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//#define clockspeed 16000000
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/*
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unsigned long schedule1Duration; //How long (uS) after calling the start callback to we call the end callback
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unsigned long schedule2Duration;
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void (*schedule1StartCallback)(); //Start Callback function for schedule1
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void (*schedule2StartCallback)();
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void (*schedule1EndCallback)(); //End Callback function for schedule1
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void (*schedule2EndCallback)();
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*/
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void initialiseSchedulers();
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void setFuelSchedule1(void (*startCallback)(), unsigned long timeout, unsigned long duration, void(*endCallback)());
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void setSchedule2(void (*startCallback)(), unsigned long timeout, unsigned long duration, void(*endCallback)());
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enum ScheduleStatus {OFF, PENDING, RUNNING};
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struct Schedule {
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unsigned long duration;
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ScheduleStatus Status;
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void (*StartCallback)(); //Start Callback function for schedule1
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void (*EndCallback)(); //Start Callback function for schedule1
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};
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Schedule fuelSchedule1;
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Schedule fuelSchedule2;
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Schedule ignitionSchedule1;
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Schedule ignitionSchedule2;
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void setup()
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{
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Serial.begin(9600);
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initialiseSchedulers();
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}
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void loop()
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{
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unsigned long curTime = micros();
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unsigned long uSInFuture = 50000; //50mS in the future
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unsigned long expectedTime = curTime + uSInFuture;
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setFuelSchedule1(callback, uSInFuture, uSInFuture, callback);
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Serial.print("Expected time: ");
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Serial.println(expectedTime);
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delay(1000);
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}
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void callback()
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{
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unsigned long arrivedTime = micros();
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Serial.print("Arrived time: ");
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Serial.println(arrivedTime);
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}
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void initialiseSchedulers()
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{
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// Much help in this from http://arduinomega.blogspot.com.au/2011/05/timer2-and-overflow-interrupt-lets-get.html
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//Fuel Schedules, which uses timer 3
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TCCR3B = 0x00; //Disbale Timer3 while we set it up
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TCNT3 = 0; //Reset Timer Count
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TIFR3 = 0x00; //Timer3 INT Flag Reg: Clear Timer Overflow Flag
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TCCR3A = 0x00; //Timer3 Control Reg A: Wave Gen Mode normal
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TCCR3B = (1 << CS12); //Timer3 Control Reg B: Timer Prescaler set to 256. Refer to http://www.instructables.com/files/orig/F3T/TIKL/H3WSA4V7/F3TTIKLH3WSA4V7.jpg
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fuelSchedule1.Status = OFF;
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fuelSchedule2.Status = OFF;
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//Ignition Schedules, which uses timer 3
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TCCR4B = 0x00; //Disbale Timer3 while we set it up
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TCNT4 = 0; //Reset Timer Count
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TIFR4 = 0x00; //Timer3 INT Flag Reg: Clear Timer Overflow Flag
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TCCR4A = 0x00; //Timer3 Control Reg A: Wave Gen Mode normal
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TCCR4B = (1 << CS12); //Timer3 Control Reg B: Timer Prescaler set to 256. Refer to http://www.instructables.com/files/orig/F3T/TIKL/H3WSA4V7/F3TTIKLH3WSA4V7.jpg
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ignitionSchedule1.Status = OFF;
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ignitionSchedule2.Status = OFF;
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}
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/*
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These 4 function turn a schedule on, provides the time to start and the duration and gives it callback functions.
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All 4 functions operate the same, just on different schedules
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Args:
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startCallback: The function to be called once the timeout is reached
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timeout: The number of uS in the future that the callback should be triggered
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duration: The number of uS after startCallback is called before endCallback is called
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endCallback: This function is called once the duration time has been reached
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*/
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void setFuelSchedule1(void (*startCallback)(), unsigned long timeout, unsigned long duration, void(*endCallback)())
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{
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if(fuelSchedule1.Status == RUNNING) { return; } //Check that we're not already part way through a schedule
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//We need to calculate the value to reset the timer to (preload) in order to achieve the desired overflow time
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//As the timer is ticking every 16uS (Time per Tick = (Prescale)*(1/Frequency))
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unsigned int absoluteTimeout = TCNT3 + (timeout / 16); //Each tick occurs every 16uS with the 256 prescaler, so divide the timeout by 16 to get ther required number of ticks. Add this to the current tick count to get the target time. This will automatically overflow as required
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OCR3A = absoluteTimeout;
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fuelSchedule1.duration = duration;
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fuelSchedule1.StartCallback = startCallback; //Name the start callback function
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fuelSchedule1.EndCallback = endCallback; //Name the start callback function
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fuelSchedule1.Status = PENDING; //Turn this schedule on
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TIMSK3 |= (1 << OCIE3A); //Turn on the compare unit (ie turn on the interrupt)
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}
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//Timer3A (schedule 1) Overflow Compare Vector
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//This needs to call the callback function if one has been provided and rest the timer
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ISR(TIMER3_COMPA_vect)
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{
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if (fuelSchedule1.Status == PENDING) //Check to see if this schedule is turn on
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{
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fuelSchedule1.StartCallback();
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fuelSchedule1.Status = RUNNING; //Set the status to be in progress (ie The start callback has been called, but not the end callback)
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unsigned int absoluteTimeout = TCNT3 + (fuelSchedule1.duration / 16);
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OCR3A = absoluteTimeout;
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}
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else if (fuelSchedule1.Status == RUNNING)
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{
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fuelSchedule1.EndCallback();
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fuelSchedule1.Status = OFF; //Turn off the schedule
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TIMSK3 &= ~(1 << OCIE3A); //Turn off this output compare unit (This simply writes 0 to the OCIE3A bit of TIMSK3)
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}
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TIFR3 = 0x00; //Timer3 INT Flag Reg: Clear Timer Overflow Flag. I'm not 100% sure this is necessary, but better to be safe
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}
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