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prova.ino

@@ -0,0 +1,94 @@
+#define samples 15
+
+uint8_t state, old_state, initial;
+uint8_t changed[samples];
+uint32_t timer[samples];
+uint16_t event = 0;
+
+volatile uint64_t overflow_count = 0;
+volatile uint64_t total_count = 0;
+
+
+int main(void) {
+  Serial.begin(9600);
+
+  TCCR2B = TCCR2B & 0b11111000 | 0x02;
+  TIMSK2 |= (1 << TIMSK2);  // enable Timer2 overflow interrupt
+  TCCR2A &= 0b11111100;     // timer2 working parameters
+  TCCR2B &= 0b11110111;
+
+  PORTC = (0 << 0); DDRC |= (1 << 0); // led A0
+  DDRB |= 0x00;     // pin 8-13 input
+  PORTB |= 0x3F;    // pull-up
+
+  start();
+
+  while (1) {
+    old_state = state;
+    state = PINB;
+
+    if (old_state != state) {
+      timer[event] = get_time();
+      changed[event] = old_state ^ state;
+      event++;
+
+      if (event == samples) {
+        sendData();
+        while (Serial.read() != 'G') ; //wait for the "go"
+        start();
+      }
+    }
+  }
+}
+
+void start() {
+  _delay_ms(1000);
+
+  TCNT2 = 0;
+  overflow_count = 0;
+  event = 0;
+
+  PORTC = (1 << 0);
+  initial = PINB;
+  state = initial;
+
+  //in futuro potrei fare in modo che time[0] è impostato qui
+}
+
+
+void sendData() {
+  PORTC = (0 << 0);   //turn off led
+
+  //initial data
+  Serial.print("S"); Serial.println("");
+  Serial.print(initial); Serial.print(":");
+  Serial.println(samples);
+
+  //data
+  for (int i = 0; i < samples; i++) {
+    Serial.print(changed[i]); Serial.print(":");
+    Serial.println(timer[i]);
+  }
+}
+
+
+//timer:
+uint32_t get_time() {
+  cli();
+  uint8_t tcnt2_save = TCNT2;
+  boolean flag_save = TIMSK2 & (1 << TIFR2); //timer2 overflow flag
+
+  if (flag_save) {
+    tcnt2_save = TCNT2;
+    overflow_count++;     //manual increment of the overflow counter
+    TIFR2 = (1 << TIFR2); //reset overflow flag to prevent execution of the ISR
+  }
+
+  total_count = (overflow_count * 256 + tcnt2_save) / 2;
+  sei();
+  return total_count;
+}
+
+ISR(TIMER2_OVF_vect) {
+  overflow_count++;
+}