Project 2 - Measuring distance of an object using ultrasonic sensor (HC-SR04)

Explanation:

1. Header files and Macro definition:
• The code starts by defining the microcontroller clock frequency (F_CPU) and includes necessary header files for AVR programming.
• #define F_CPU 16000000L sets the CPU clock frequency to 16 MHz.
2. Variable Declaration:
• volatile int TimerOverflow = 0; declares a volatile integer variable TimerOverflow and initializes it to 0. This variable is used to count timer overflows.
3. Timer Overflow Interrupt Service Routine (ISR):
• ISR(TIMER1_OVF_vect) is an interrupt service routine that is executed when Timer1 overflows.
4. Main Function:
• int main(void) is the main function where the program execution begins.
5. Port Configuration:
• DDRA, DDRB, and DDRD are Data Direction Registers, used to configure the direction of data flow for each port (input or output).
• PORTD is set to enable pull-up resistors on all pins.
6. Timer Configuration:
• TIMSK = (1 << TOIE1); enables Timer1 overflow interrupts.
• TCCR1A = 0; configures Timer1 for normal operation.
7. LCD Initialization:
• LCD_Init(); initializes the LCD module.
8. Ultrasonic Sensor Measurement Loop:
• The while(1) loop contains the code for measuring the distance using an ultrasonic sensor.
• The trigger pin is set high and low to initiate the ultrasonic pulse.
• Timer1 is configured and used to measure the time it takes for the pulse to return.
9. Distance Calculation:
• The count is calculated based on the timer values, and the distance is calculated using a formula (distance = (double)count / 932.944).
10. LCD Display:
• The distance value is displayed on an LCD screen.
11. Delay:
• _delay_ms(50); introduces a delay of 50 milliseconds.