Description of the Real-Time Clock (RTC) Project

This project is a Real-Time Clock (RTC) implemented on an AVR microcontroller. It features a user interface for setting the clock using a keypad and displays the current time on a seven-segment display. The project utilizes Timer2 for keeping track of seconds, and it supports hours, minutes, and seconds display.

Project Components

1. LCD Display: Used for user interactions, such as setting the time.
2. Keypad: Allows the user to input the hour, minute, and second values to set the clock.
3. Seven-Segment Display: Shows the current time in hours, minutes, and seconds.
4. Timer2: Manages timekeeping by generating interrupts every second.

Key Features

1. Time Setting: Users can set the hour, minute, and second values using the keypad.
2. Real-Time Clock Display: The current time is continuously displayed on the seven-segment display.
3. Timer Interrupt: Timer2 is used to increment the seconds counter every second, which in turn updates the minutes and hours.

Detailed Explanation

1. Initialization

• LCD Initialization: LCD_init() initializes the LCD display for interaction.
• Keypad Initialization: KEYBAD_init() sets up the keypad for user input.
• Seven-Segment Display Initialization: seven_seg_init_port() prepares the port connected to the seven-segment display.
• Timer2 Initialization: TIMER2_normal_init_with_interrupt() configures Timer2 in normal mode with a prescaler to generate a 1-second interrupt.

2. Setting Clock:

• Pressing 'A' triggers setting the clock time.
• Sequentially input hours, minutes, and seconds via the keypad.

3. Displaying Clock:

• Multiplexing Technique: Multiplexing involves sequentially turning on one seven-segment display at a time while quickly switching between them to give the illusion that all displays are on simultaneously.
• Multiplexing Implementation: The code cycles through each digit of the time (hours, minutes, seconds) and sends the corresponding data to the seven-segment display before moving to the next digit.
• Segments are updated in a rapid sequence to create the illusion of continuous display.

4. Timekeeping

• Timer2 Interrupt: Timer2 generates an interrupt every second (1s) to update the seconds counter:

  • ISR(TIMER2_OVF_vect) increments the seconds_counter every second.

• Display Update: The display_clock() function:

  • Updates the seven-segment display to show the current hours, minutes, and seconds.
  • Rotates through the seven-segment display positions to show each time unit.
  • Handles rollover of seconds to minutes, and minutes to hours:
    • If seconds_counter reaches 60, it resets to 0 and increments minutes_counter.
    • If minutes_counter reaches 60, it resets to 0 and increments hours_counter.
    • If hours_counter reaches 24, it resets to 0.

5. Timer2 Configuration

• Timer Mode: Configured in normal mode with no waveform generation (WGM20 and WGM21 are cleared).
• Prescaler: Set to 128 to achieve a timer clock frequency of 256 Hz (based on a 32.768 kHz external clock source). This configuration results in a timer overflow interrupt every second.
• Interrupt Enable: Timer overflow interrupt is enabled with SET_BIT(TIMSK, TOIE2).

This project demonstrates a basic real-time clock application using an AVR microcontroller. It incorporates:

• User Input: For setting the time through a keypad.
• Timekeeping: Managed by Timer2 and displayed on a seven-segment display.
• Interrupts: To keep track of the time with a 1-second resolution.

This RTC project provides a practical example of integrating various components and peripherals to create a functional timekeeping system with user interaction.