CODEWITHSUNDEEP
arduinocounteratmega
oliver
oliver

Reputation: 2901

Why is TCNT1 not counting up on Atmega328?

I have the following code for the Arduino with Atmega328 and a common 16x2 LCD. The LCD is working, but it is always showing the starting value "333" of the Timer 1 counter TCNT1. Why? I have read the datasheet of the 328 over and over again, but I don't get it.

    #include <LiquidCrystal.h>

    const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
    LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

    const int lcdContrastPin = 6, lcdBackligthPin = 10;

    void setup() 
    {
      // tutn on LCD backlight and contrast
      pinMode(lcdContrastPin, OUTPUT);
      pinMode(lcdBackligthPin, OUTPUT);

      // fine-tuning contrast could be done by PWM on lcdContrastPin
      digitalWrite(lcdContrastPin, LOW);
      digitalWrite(lcdBackligthPin, HIGH);

      lcd.begin(16, 2);

      // configure Timer1
      TCCR1A = 0; // no waveform generation
      TCCR1B = 0x00000010; // frequency divider 8 (i.e. counting with 2 MHz)
      TCCR1C = 0;
      TIFR1 = 0x00100000; // clear Input Capture Flag
      TCNT1 = 333;
    }

    void loop() 
    {
      int currentTimerValue = TCNT1;

      lcd.setCursor(0, 0);
      lcd.print("TCNT1=");
      lcd.print(currentTimerValue);
      lcd.println("      ");

      delay(50); 
    }

Upvotes: 0

Views: 890

Answers (1)

oliver
oliver

Reputation: 2901

Stupid me! In a lapse of consciousness I took 0x00000010 as a binary number instead of as a hexadecimal which it is. As a result I set the all clock selection bits to 0 which means the timer stops.

After replacing 0x00000010 by 0b00000010 (the true binary number) everything works as expected now:

      TCCR1B = 0b00000010; // frequency divider 8 (i.e. counting with 2 MHz)
      TCCR1C = 0;
      TIFR1 = 0b00100000; // clear Input Capture Flag

Upvotes: 1

Related Questions