🔌 Analog to Digital Conversion using PIC16F877A

📌 Project Overview

This project demonstrates Analog-to-Digital Conversion (ADC) using the PIC16F877A microcontroller. The ADC module converts analog signals (like sensor outputs) into digital values that can be processed by the microcontroller.

This is useful in applications such as:

• Temperature sensing 🌡️
• Light intensity measurement 💡
• Voltage monitoring 🔋
• Sensor interfacing systems

---

🧠 Features

• Uses built-in 10-bit ADC of PIC16F877A
• Supports multiple input channels (AN0–AN7)
• Simple and efficient ADC read function
• Compatible with MPLAB XC8 compiler
• Real-time analog signal conversion

---

🛠️ Hardware Requirements

• PIC16F877A Microcontroller
• Crystal Oscillator (16 MHz)
• Capacitors (22pF typically)
• Potentiometer / Analog Sensor
• Breadboard & Connecting Wires
• Power Supply (5V)
• LCD (optional for display)

---

💻 Software Requirements

• MPLAB X IDE
• XC8 Compiler
• Proteus (optional for simulation)

---

⚙️ Circuit Diagram

• Connect analog input (e.g., potentiometer) to AN0 (RA0)
• Connect Vref+ and Vref- properly (or use default VDD/VSS)
• Optional: Connect LCD for displaying ADC values

---

🧾 Code Explanation

🔹 ADC Initialization

void adc_init()
{
    ADCON0 = 0x01;  // Enable ADC, select channel 0
    ADCON1 = 0x80;  // Right justified, Fosc/32
}

🔹 ADC Read Function

unsigned int adc_read(unsigned int channel)
{
    if(channel > 7) return 0;

    ADCON0 &= 0xC5;              // Clear channel bits
    ADCON0 |= (channel << 3);    // Select channel

    __delay_us(20);              // Acquisition time

    GO_nDONE = 1;                // Start conversion
    while(GO_nDONE);             // Wait for completion

    return ((ADRESH << 8) + ADRESL); // Combine result
}

---

📊 How It Works

1. Analog signal is applied to an ADC channel (e.g., AN0)

2. ADC converts the analog voltage into a 10-bit digital value (0–1023)

3. The result is stored in:

   • ADRESH (High byte)
   • ADRESL (Low byte)

4. Combined result gives full digital output

---

▶️ Usage

1. Initialize ADC using adc_init()

2. Call adc_read(channel) to get digital value

3. Use the value for:

   • Display (LCD/Serial)
   • Control systems
   • Decision making

---

📈 Example Output

Analog Voltage	Digital Value
0V	0
2.5V	~512
5V	1023

---

🚀 Applications

• Embedded systems
• Sensor interfacing
• Data acquisition systems
• Industrial automation

---

📚 Future Improvements

• Add LCD display output
• Implement UART for serial monitoring
• Add multiple sensor inputs
• Improve accuracy with calibration

---

👨‍💻 Author

Akash RA

---

📜 License

This project is open-source and available under the MIT License.

---

⭐ Support

If you found this project helpful, give it a ⭐ on GitHub!