Practical Arduino C

Page 119

Page 120

const int RED_PIN = 11;
const int GREEN_PIN = 5;
const int BLUE_PIN = 6;
void setup() {
  pinMode(RED_PIN, OUTPUT);
  pinMode(GREEN_PIN, OUTPUT);
  pinMode(BLUE_PIN, OUTPUT);  
}
void loop() {
    setColour(255, 0, 0);  // red
//setColour(0, 255, 0);  // green
//setColour(0, 0, 255);  // blue
//setColour(255,255,255); // white (well blueish white)
  delay(1000);
  setColour(0, 0, 0);  //off
  delay(1000);
}
void setColour(byte red, byte green, byte blue)
{
  analogWrite(RED_PIN, red);
  analogWrite(GREEN_PIN, green);
  analogWrite(BLUE_PIN, blue);  
}

Page 122

const int DIG_RED_PIN = 7;
const int MSECS_ON = 250; // 25% of 1,000
const int MS_SEC = 1000;
void setup() {
  pinMode(DIG_RED_PIN, OUTPUT);
}
void loop() {
  digitalWrite(DIG_RED_PIN, HIGH);
  delayMicroseconds(MSECS_ON);
  digitalWrite(DIG_RED_PIN, LOW);
  delayMicroseconds(MS_SEC - MSECS_ON);
}

Page 123

void setup() {
  pinMode(LED_BUILTIN, OUTPUT); // setup the LED pin
  noInterrupts(); // disable all interrupts
  TCCR1A = 0; // Timer control register
  TCCR1B = 0;
  // bit twiddling to set signal division and mode
  TCNT1 = 3036; // Set counter to start value 65536 - (16Mhz / 256)
  TCCR1B |= (1 << CS12); // 256 prescaler
  TIMSK1 |= (1 << TOIE1); // set timer overflow interrupt
  interrupts(); // re-enable interrupts
}
ISR(TIMER1_OVF_vect){
  TCNT1 = 3036; // reset timer for 1 sec blink then toggle LED
  digitalWrite(LED_BUILTIN, digitalRead(LED_BUILTIN) ^ 1);
}
void loop() {
}

Page 124

void setup() {
  pinMode(LED_BUILTIN, OUTPUT); // setup the LED pin
  noInterrupts(); // disable all interrupts
  TCCR1A = 0; // Timer control register
  TCCR1B = 0;
  TCNT1 = 0; // Zero timer counter register for Timer1
  // now the register bit twiddling
  OCR1A = 62500; // Set the compare match register for 1Hz
  TCCR1B |= (1 << WGM12); // CTC mode
  TCCR1B |= (1 << CS12); // 256 prescaler
  TIMSK1 |= (1 << OCIE1A); // set timer compare interrupt
  interrupts(); // re-enable all interrupts
}
// An output compare interrupt on Timer1 calls this ISR
ISR(TIMER1_COMPA_vect){ // timer compare interrupt service routine
  digitalWrite(LED_BUILTIN, digitalRead(LED_BUILTIN) ^ 1); // toggle LED
}
void loop() {
}

Page 125

void setup() {
  pinMode(LED_BUILTIN, OUTPUT); // setup the LED pin
  noInterrupts(); // disable all interrupts
  TCCR2A = 0; // Timer control register
  TCCR2B = 0;
  TCNT2 = 0; // Set counter to 0
  OCR2A = 240; //Compare match register
  TCCR2A |= (1 << WGM21); // CTC Mode
  TCCR2B |= (1 << CS22) | (1 << CS20) | (1 << CS21); // max prescaler
  TIMSK2 |= (1 << OCIE2A); // set timer compare interrupt
  interrupts(); // re-enable interrupts
}
ISR(TIMER2_COMPA_vect){
  digitalWrite(LED_BUILTIN, digitalRead(LED_BUILTIN) ^ 1);
}