4x4 Matrix Keypad Interrfacing with the AT89C51 Microcontroller (Assembly Code and Proteus Simulation).
Using a 1602 LCD with microcontrollers like the 8051 (or any other microcontroller) and simulating the circuit in Proteus requires several steps. The 1602 LCD is a common 16x2 character display used in embedded systems to display information.
Note: The resistor network RN1 in the Proteus schematic is needed in the simulator (while it is PORT "0") only, but not on real hardware. It has been successfully tested without external resistor pull-ups.
This project demonstrates the interfacing of an LCD and a 4x4 keypad with the AT89C51 Microcontroller, part of the 8051 MCU family. This setup allows for input and output operations, making it a practical example for educational purposes and embedded systems applications.
The program is written in Assembly language, optimized for efficiency and performance, and the circuit is simulated using Proteus (Version 8.9). This repository includes:
- Assembly Code for LCD and keypad interfacing
- Precompiled HEX File for easy microcontroller programming
- Proteus Simulation Circuit demonstrating the project functionality
The project has been successfully tested on both simulation and real hardware setups, ensuring reliability and accuracy.
AT89C51 Microcontroller | 8051 | Assembly Language | Simulation | Proteus | Microcontroller Programming | LCD Interfacing | Keypad Interfacing
| Feature | Description |
|---|---|
| 📟 LCD Display | Displays user input and output results |
| ⌨️ 4x4 Keypad Input | User-friendly interface for data entry |
| 🖥️ Proteus Simulation | Ready-to-use simulation circuit compatible with Proteus 8.9 |
| 💾 Assembly Programming | Optimized assembly code for efficient execution on the AT89C51 |
| 🛠️ Real Hardware Support | Successfully tested on actual hardware for reliable performance |
| File | Description |
|---|---|
AT89C51_LCD_Keypad.asm |
Assembly source code for the AT89C51 microcontroller |
AT89C51_LCD_Keypad.hex |
Precompiled HEX file for direct microcontroller upload |
Proteus_Simulation.pdsprj |
Proteus Design Suite simulation file |
| Screenshots | Visual demonstrations from the Proteus simulation |
| Hardware Component | Description |
|---|---|
| AT89C51 Microcontroller | Central unit managing input and output operations |
| LCD | 16x2 LCD for displaying data and results |
| 4x4 Keypad | Input interface for entering commands and numbers |
| Transistors (e.g., NPN) | Used to interface the microcontroller with the LCD and other components |
| Resistors | Current-limiting resistors to protect components from overcurrent |
| Power Supply | A 5V DC power supply for the microcontroller and LCD circuit |
Each component, including the keypad, is connected to the microcontroller's input pins, while resistors are used throughout the circuit to ensure proper current control.
The 1602 alphanumeric LCD is a type of liquid crystal display that can show alphanumeric characters. It is one of the most common character-based LCD modules used in embedded systems for displaying text and simple symbols. The "1602" designation refers to its 16 columns and 2 rows, meaning it can display 16 characters per line and a total of 32 characters across its two lines.
- Display Size: It can display up to 32 characters (16 characters on each row).
- Character Set: It supports a 5x8 dot matrix per character, allowing for the display of basic letters, numbers, punctuation marks, and some special characters.
- Backlight: Many models come with an optional LED backlight, making the display readable in low-light conditions.
- Contrast Adjustment: The contrast of the characters on the LCD can be adjusted using a potentiometer connected to the V0 pin.
- 4-bit or 8-bit Communication: It can operate in either 4-bit or 8-bit data mode, meaning it can communicate with a microcontroller using 4 or 8 data lines.
| Pin | Name | Description |
|---|---|---|
| 1 | VSS | Ground (GND) |
| 2 | VDD | Power supply (+5V) |
| 3 | V0 | Contrast adjustment (via potentiometer) |
| 4 | RS | Register Select (0 for command, 1 for data) |
| 5 | RW | Read/Write (0 for write, 1 for read) |
| 6 | E | Enable pin (trigger) |
| 7-14 | D0-D7 | Data pins (for 4/8-bit mode) |
| 15 | LED+ | LED backlight anode (+5V) |
| 16 | LED- | LED backlight cathode (GND) |
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Data/Command Modes: The 1602 LCD operates in two modes:
- Command Mode: Used to send commands to the LCD, such as clearing the screen, setting the cursor position, etc. This is controlled by setting the RS pin low (RS = 0).
- Data Mode: Used to send characters to be displayed on the screen. This is controlled by setting the RS pin high (RS = 1).
-
4-bit vs 8-bit Communication:
- In 8-bit mode, all 8 data pins (D0-D7) are used to send data or commands.
- In 4-bit mode, only the upper 4 data pins (D4-D7) are used, and data is sent in two cycles (high nibble first, then low nibble).
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Clone this repository:
git clone https://github.com/gmostofabd/AT89C51_LCD_Keypad_Interfacing.git
-
Compile the Assembly Code: Open the
AT89C51_LCD_Keypad.asmfile in MIDE-51 or any compatible IDE, and compile it to generate the HEX file. -
Simulate in Proteus: Open Proteus Design Suite, load the provided simulation file, and run the simulation to observe the interface's functionality.
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Program the Microcontroller: For real hardware applications, upload the HEX file to the AT89C51 microcontroller using a compatible programmer.
-
Test the Circuit: Assemble the hardware according to the provided circuit diagram, power it on, and verify functionality by using the keypad to enter data.
The 16x2 LCD displays the data processed by the microcontroller, providing immediate feedback on user inputs.
- Number Keys: Input numeric values through the keypad and view them on the LCD.
- Function Keys: Specific