Hello friends! Today, we are going to design a simple calculator with an 8051 microcontroller in Proteus. We will combine a 4×4 keypad, a 20×4 LCD and an AT89C51 so that you can enter an arithmetic operation and see its result on the display. We have already covered LCD interfacing and keypad interfacing with the 8051 . Those lessons provide the input and output functions. Here, we will add the application logic that decides which key is valid and when a calculation should take place. This remains a single-digit calculator, like the original project. It accepts two operands from zero through nine and supports addition, subtraction, multiplication and integer division. We will also handle negative results, invalid input and division by zero explicitly. Figure: Original 8051 calculator showi ...
Hello friends! Today, we are going to interface a 4×4 keypad with an 8051 microcontroller in Proteus. We will read the pressed key through the AT89C51 and display its character on a 20×4 LCD, so we can see exactly what the program receives. This project builds on our LCD interfacing tutorial . The display remains our output device, while the keypad becomes an input device. Together, they form the basic user interface for a calculator, menu, password entry system or small control panel. I will explain the keypad matrix before discussing the program. We will then add debouncing, prevent one held button from producing repeated characters and keep typed text within the upper two LCD rows. The original simulation, images and download are preserved for reference. Figure: Original keypad characte ...
Hello friends! Today, we are going to interface a character LCD with an 8051 microcontroller in Proteus. We will use an AT89C51 to send commands and text to the display, then explain how the LCD decides where each character should appear. This is the next step after our 8051 serial communication tutorial . A serial terminal is useful during development, while an LCD lets a project present information directly to its user. Both are valuable when we need to observe values inside an embedded program. The original project actually uses an LM044L-style 20×4 display, so we will follow that arrangement throughout this lesson. A 20×4 LCD has twenty character positions on each of four rows. The same interface principles apply to many 16×2 modules, but their visible layout and row handling are diffe ...
