https://github.com/gmostofabd/8051-lcd
📚 This repository demonstrates how to interface a 16x2 alphanumeric LCD with the 8051 Microcontrollers (AT89S52) using Assembly Language Programming. The project is designed to showcase a practical example of sending data from the 8051 microcontroller to an LCD and includes Proteus simulation files for testing, modify, debug and visualization.
https://github.com/gmostofabd/8051-lcd
4bit 8051 8bit assembly circuit code download experiment hex interfacing language lcd microcontroller mode programming proteus simulation
Last synced: about 1 month ago
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📚 This repository demonstrates how to interface a 16x2 alphanumeric LCD with the 8051 Microcontrollers (AT89S52) using Assembly Language Programming. The project is designed to showcase a practical example of sending data from the 8051 microcontroller to an LCD and includes Proteus simulation files for testing, modify, debug and visualization.
- Host: GitHub
- URL: https://github.com/gmostofabd/8051-lcd
- Owner: gmostofabd
- Created: 2021-05-23T08:03:39.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2024-09-25T17:21:05.000Z (7 months ago)
- Last Synced: 2025-01-19T23:44:14.373Z (3 months ago)
- Topics: 4bit, 8051, 8bit, assembly, circuit, code, download, experiment, hex, interfacing, language, lcd, microcontroller, mode, programming, proteus, simulation
- Language: HTML
- Homepage: https://gmostofabd.github.io/8051-LCD/
- Size: 1.06 MB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# ⚙️ **LCD Interfacing with 8051 Microcontroller**
This repository demonstrates interfacing a **16x2 alphanumeric LCD** with the **8051 Microcontroller** using **Assembly language**. The project is designed to show how to send data from the **8051 microcontroller** to an LCD. It includes **Proteus simulation files** for testing and visualization.
Fig-1: 8051 Microcontroller LCD Interface (Schematic Diagram).
The figure above shows the circuit schematic for interfacing the **16x2 LCD** with the **AT89C51 Microcontroller**. It includes essential connections for data transfer, control, and power, enabling the display of alphanumeric characters using **8-bit data mode**.
---
## 🔑 **Keywords**
[**AT89C51 Microcontroller**](https://en.wikipedia.org/wiki/Intel_MCS-51) | [**Assembly Language**](https://en.wikipedia.org/wiki/Assembly_language) | [**Proteus**](https://www.labcenter.com/) | [**16x2 LCD**](https://en.wikipedia.org/wiki/Liquid-crystal_display) | [**LCD Interfacing**](https://en.wikipedia.org/wiki/Liquid-crystal_display)
---
## ⚙️ **Project Overview**
This project demonstrates **LCD interfacing** with the **[AT89C51 Microcontroller](https://www.atmel.com/products/microcontrollers/8051.aspx)**. It is useful for educational purposes and embedded systems applications, allowing the microcontroller to display data on the LCD.
---
## 🔧 **Key Features**
| Feature | Description |
|-------------------------------|-----------------------------------------------------------------------------|
| 📟 **LCD Display** | Displays data entered or processed by the microcontroller |
| 🖥️ **Proteus Simulation** | Includes a ready-to-use simulation circuit compatible with Proteus 8.9 |
| 💾 **Assembly Programming** | Optimized assembly code for efficient execution on the AT89C51 |
| 🛠️ **Real Hardware Test** | Successfully tested on actual hardware for reliable performance |
---
## 📦 **What’s Included?**
| **File** | **Description** |
|------------------------|-------------------------------------------------------------------------|
| **Assembly Code** | The core assembly code for initializing and operating the LCD. (`exampleproject.asm`) |
| **Proteus Simulation** | Simulation file for testing the LCD interface in Proteus. (`exampleproject.pdsjr`) |
| **HEX File** | Compiled HEX file for uploading to the 8051 microcontroller. (`exampleproject.hex`) |
| **Test Run Image** | Image showing the test run result. |
---
## 🖥️ **Installation & Usage**
### Step-by-Step Guide:
1. **Clone this repository**:
```bash
git clone https://github.com/gmostofabd/8051-LCD.git
```
2. **Compile the Assembly Code**:
Open the `AT89C51_LCD_Keypad.asm` file in **MIDE-51** or any compatible IDE, and compile it to generate the **HEX file**.
3. **Simulate in Proteus**:
Open **Proteus Design Suite**, load the provided simulation file, and run the simulation to observe the interface's functionality.
4. **Program the Microcontroller**:
For real hardware, upload the **HEX file** to the AT89C51 microcontroller using a compatible programmer.
5. **Test the Circuit**:
Assemble the hardware based on the provided circuit diagram, power it on, and verify the LCD's functionality.
---
## 🛠️ **Components Used**
| **Component** | **Description** |
|----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------|
| AT89C51 Microcontroller | The core of the project, programmed in Assembly language to control the LCD. |
| 16x2 LCD | Displays the output of the microcontroller in alphanumeric form. |
| Crystal Oscillator (11.0592 MHz) | Provides a clock signal to the microcontroller for accurate timing. |
| 33pf Capacitors (2x) | Used with the crystal oscillator to stabilize the clock signal, connected between XTAL1 and XTAL2 of the microcontroller and ground. |
| 100 Ohm Resistor | Limits current in the circuit to protect components. |
| 10K Variable Resistor (Potentiometer) | Adjusts the contrast of the LCD, wired between VCC and GND, with the wiper connected to the contrast pin (V0) of the LCD. |
| Push-button Switch (Reset) | Connected to the RST pin of the microcontroller for manual reset, with a pull-down resistor for stability. |
| Jumper Wires | Connects components as needed. |
---
## 🌐 **LCD Display**
A **Liquid Crystal Display (LCD)** provides a useful interface for embedded systems. The **16x2 LCD** displays textual information across two rows, each capable of showing 16 characters, with each character occupying a 5x7 matrix space on the screen.
---
## 🌐 **16×2 LCD Pin Diagram**
---
## 🌐 **Programming LCD with 8051**
To interface with the **16x2 LCD**, follow these mandatory steps:
1. **Initialization**:
- Set the LCD to 8-bit mode by sending initialization commands.
2. **Set RS and RW Pins**:
- **RS**: Set to `0` for commands, `1` for data.
- **RW**: Set to `0` for writing, `1` for reading (not often used in basic setups).
3. **Send Commands/Data**:
- Place the command or data in the data register and trigger the **Enable Pin**.
4. **Enable Pulse**:
- Toggle the **Enable Pin** to send the command/data.
5. **Delay**:
- Wait briefly after each command/data transfer to allow the LCD to process it.
---
### Assembly Code for 8-Bit Mode LCD Interfacing
```assembly
; -----------------------------
; LCD Interfacing in 8-Bit Mode (lcd_8bit.asm)
; -----------------------------
ORG 00H ; Set origin to address 00H
MOV SP, #70H ; Initialize stack pointer at address 70H
MOV PSW, #00H ; Set program status word to 00H
LCD_IN:
MOV A, #38H ; Initialize LCD for 2 lines, 5x7 matrix
LCALL COMNWRT ; Call command write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #0EH ; Display ON, Cursor ON
LCALL COMNWRT ; Call command write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #01H ; Clear LCD display
LCALL COMNWRT ; Call command write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #06H ; Shift cursor to the right
LCALL COMNWRT ; Call command write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #85H ; Set cursor at line 1, position 1
LCALL COMNWRT ; Call command write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'E' ; Display letter 'E'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'X' ; Display letter 'X'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'P' ; Display letter 'P'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #':' ; Display colon ':'
LCALL DATAWRT ; Call data write subroutine
MOV A, #'0' ; Display number '0'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'4' ; Display number '4'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #0C3H ; Set cursor at line 2, position 1
LCALL COMNWRT ; Call command write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'8' ; Display number '8'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #' ' ; Display space
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'B' ; Display letter 'B'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'i' ; Display letter 'i'
LCALL DATAWRT ; Call data write subroutine
MOV A, #'t' ; Display letter 't'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #' ' ; Display space
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'L' ; Display letter 'L'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'C' ; Display letter 'C'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
MOV A, #'D' ; Display letter 'D'
LCALL DATAWRT ; Call data write subroutine
LCALL DELAY ; Give LCD some time
SJMP $ ; Infinite loop
; -----------------------------
; Command Write Subroutine
; -----------------------------
COMNWRT:
LCALL READY ; Prepare for sending command to LCD
MOV P1, A ; Copy content of register A to port 1
CLR P3.4 ; Set RS = 0 for command mode
CLR P3.5 ; Set R/W = 0 for write mode
SETB P3.6 ; Set E high for pulse
ACALL DELAY ; Give LCD some time
CLR P3.6 ; Set E low for H-to-L pulse
RET
; -----------------------------
; Data Write Subroutine
; -----------------------------
DATAWRT:
LCALL READY ; Prepare for writing data to LCD
MOV P1, A ; Copy content of register A to port 1
SETB P3.4 ; Set RS = 1 for data mode
CLR P3.5 ; Set R/W = 0 for write mode
SETB P3.6 ; Set E high for pulse
ACALL DELAY ; Give LCD some time
CLR P3.6 ; Set E low for H-to-L pulse
RET
; -----------------------------
; Ready Check Subroutine
; -----------------------------
READY:
SETB P1.7 ; Set P1.7 to indicate readiness
CLR P3.4 ; Clear RS
SETB P3.5 ; Set R/W = 1 for read mode
WAIT:
CLR P3.6 ; Clear E
ACALL DELAY ; Wait for delay
SETB P3.6 ; Set E high
JB P1.7, WAIT ; Wait until P1.7 is high (LCD ready)
RET
; -----------------------------
; Delay Subroutine
; -----------------------------
DELAY:
MOV R3, #50 ; Set outer loop count (50 or higher for fast CPUs)
HERE2:
MOV R4, #255 ; Set inner loop count (255)
HERE:
DJNZ R4, HERE ; Decrement R4 and repeat until it reaches 0
DJNZ R3, HERE2 ; Decrement R3 and repeat until it reaches 0
RET
END ; End of program
```
### Code Explanation
- **LCD Initialization**: The `LCD_INIT` procedure sets the LCD in 8-bit mode, turns on the display, and clears it.
- **Command and Data Functions**: `LCD_CMD` sends commands to the LCD, while `LCD_DATA` sends data (characters).
- **String Sending**: The `SEND_STRING` procedure sends a null-terminated string to the LCD for display.
- **Main Program**: The `MAIN` procedure initializes the LCD and sends the string to display.
### Usage
1. **Save the Code**: Copy this code into a file named `lcd.asm`.
2. **Compile**: Use a compatible assembler to compile the code.
3. **Simulate or Upload**: Use Proteus for simulation or upload it to the AT89C51 microcontroller.
## 🌐 **LCD Interfacing with 8051 – Working**
Upon powering the circuit, the **AT89C51 microcontroller** initializes the LCD and sends a message to be displayed. This can be tested through simulation or real hardware.
---
## 📜 **LCD Commands Table**
| **Command** | **Hex Code** | **Description** |
|-----------------------------------|--------------|-------------------------------------------------------|
| **Clear Display** | `0x01` | Clears the LCD and resets the cursor to home position. |
| **Return Home** | `0x02` | Returns the cursor to the home position. |
| **Entry Mode Set** | `0x04` | Sets the entry mode; cursor moves to the right. |
| **Display ON/OFF Control** | `0x0C` | Turns the display on with the cursor off. |
| **Cursor ON/OFF Control** | `0x0E` | Turns the cursor on, but without blinking. |
| **Blinking Cursor ON** | `0x0F` | Turns the blinking cursor on. |
| **Shift Display Right** | `0x1C` | Shifts the entire display to the right. |
| **Shift Display Left** | `0x18` | Shifts the entire display to the left. |
| **Function Set** | `0x38` | Sets the interface to 8-bit, 2-line mode with 5x7 dots. |
| **Set Cursor Position** | `0x80` | Sets the cursor position to the specified address. |
| **Scroll Display Right** | `0x1C` | Scrolls the display right. |
| **Scroll Display Left** | `0x18` | Scrolls the display left. |
| **Set CGRAM Address** | `0x40` | Sets the address for the character generator RAM. |
| **Set DDRAM Address** | `0x80` | Sets the address for the display data RAM. |
---
## 📝 **Tasks**
- Verify the connections based on the schematic.
- Modify the code to display different messages.
- Experiment with the contrast and observe its effects.
---
## 🔗 **Resources**
- **8051 Microcontroller Reference**: [Datasheet](https://www.atmel.com/products/microcontrollers/8051.aspx)
- **LCD Datasheet**: [HD44780 LCD Controller](https://www.sparkfun.com/datasheets/LCD/HD44780.pdf)
---
### 🛠️ **Future Work**
- Adding more functionalities such as scrolling text, custom characters, and additional interfacing techniques like 4-bit mode.
---
```
---