Button-Controlled LED Brightness
Button-Controlled LED Brightness
The program starts off initializing F_CPU to 16MHz, defining the clock frequency of the microcontroller. In the while loop, DDRB is utilized to set the data direction of the registers. DDB5 is used to configure PINB5 as the output since it is the pin for the LED. DDB7 is used to set PINB7 as the input for the button. PORTB is used to write data to the pins on Port B, activating the pull-up resistor for PINB7, ensuring that it reads a high value when the button is not pressed. TCCR0A is the Timer/Counter Control Register A for Timer 0. It sets the WGM01 bit to configure the timer in CTC (Clear Timer on Compare Match) mode. This mode allows the timer to reset to zero when it reaches a specified count (in OCR0A). OCR0A is the output compare register A for Timer 0. It sets OCR0A to 157, the value in which timer 0 will count to before resetting to zero in CTC mode. OCR0B is also an output compare register for timer 0, however, it is initialized to 0 as it is incremented or decremented based on button pressed to control the brightness of the LED. TCCR0B is the Timer/Counter Control Register B for Timer 0. TCCR0B uses CS02 and CS00) to set the prescaler to 1024, slowing down the timer's counting speed and starting the timer. PINB is used to read the current state of the pins on Port B, checking whether the button connected to pin B7 is pressed. TIFR0 is the Timer/Counter Interrupt Flag Register for Timer 0. It is used to wait for the overflow events for OCR0B and OCR0A, respectively. After the wait, TIFR0 is used to clear the corresponding overflow flags.