add exercise sheets

uni/mmme/3085_computer_engineering_and_mechatronics/res/Generate_PWM_Skeleton_Mega.ino

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+#include <avr/io.h>
+
+
+void setup() 
+{ 
+  DDRB |= (1<<7);  // Set pin 13 as output
+  TCCR1A = (1<<WGM11) | (1<<COM1C1); 
+  TCCR1B = (1<<WGM12) | (1<<WGM13) | (1<<CS10);
+  TCCR1C = 0;    // No force output compare
+  ICR1 = 799;   // Set PWM frequency noting prescale if any
+  OCR1C = 79;  // Set PWM duty cycle as a fraction of ICR1
+}
+
+void loop()
+{
+}
+
+
+

uni/mmme/3085_computer_engineering_and_mechatronics/res/Generate_and_Measure_Mega.ino

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+
+// Program to generate and count pulses using hardware only.
+// Also uses interrupt to handle register overflow.
+// For Arduino Mega only, as T/C 1 Compare Output Channel C is linked to pin 13. 
+// Frequency generation loosely based on code within "Newbie's Guide to AVR Timers".
+// The code is revised by Abdelkhalick Mohammad for MMME3085 Module.
+
+#include <avr/io.h>
+
+unsigned long bigLaps; // To record how many times T/C5 overflows
+
+void setup() 
+{ 
+  Serial.begin(9600);
+
+  // ===Timer/Counter 5 settings to count input pulses ====
+
+  //set pin T5 as input (external); this is pin 47 (Arduino Mega pin mapping) 
+  pinMode(47, INPUT);// set pin to input
+  
+  TCCR5A=0;// No waveform generation needed (T/C is counting only)
+  TCCR5B=(1<<CS50)|(1<<CS51)|(1<<CS52);// Normal mode, external clock on rising edge 
+  TCCR5C=0;//No force output compare (we will not study about this in the module)
+  TCNT5=0;//Initialise counter register to zero
+  TIMSK5=(1<<TOIE5);//When the T/C reach its maximum, an interrupt will be activated
+  bigLaps=0;//When an overflow happens, we will increase this bigLaps by 1
+
+  sei();// Enable all active interrupts
+  
+  // === Timer/Counter 1 settings to generate pulses with different frequencies ===
+
+  DDRB|=(1 << 7);//T/C1 channel C is connected to pin 13, set it as output
+  TCCR1B=(1 << WGM12 );//Configure T/C1 for CTC mode
+  TCCR1A=(1 << COM1C0 );//Enable T/C1 Compare Output channel C in toggle mode
+ // OCR1A= 7;//Set CTC compare value to 2 MHz at 16MHz AVR clock with no prescaling
+ // TCCR1B|= (1 << CS10 ) ;//Start T/C1 at Fcpu with no prescaling (i.e., 16MHz)
+  OCR1A=1249;//Set CTC compare value to 200 Hz at 16MHz AVR clock with 1/64 prescaling
+  TCCR1B|= (1 << CS10 )|(1 << CS11 );// Start T/C1 at Fcpu (i.e., 16MHz)
+}
+
+// === This is a routine which will be called if an overflow happens in T/C5 ===
+ISR(TIMER5_OVF_vect )
+{
+  bigLaps++; //when this runs, you had 65365 pulses counted
+}
+
+ unsigned long Current_Count=0;//A variable to store the total number of pulses
+
+void loop() {
+ Current_Count = TCNT5 + bigLaps*65536;
+  Serial.println(Current_Count); // Print the current number of pulses
+  delay(1000); // Intervals between each two consecutive prints
+}