Interfacing AT89C20051 using KEIL C

Learn and experiment yourself to see how to write a simple program using C language for the AT89C2051.Write a C source program, compile, and download the HEX code to the chip directly, connect DC adapter and debug the program until it works to the designed objective.


The purpose of this page is to provide beginners with a head start to program in C language to do simple experiment with the AT89C2051 microcontrollers from ATMEL. Below are a few experiments : -

interfacing to Eight LEDs
  • Interfacing to 7-segment display
  • Interfacing to 5 x 7 Matrix LED display
  • interfacing to 16 x 1 LCD
  • interfacing to I2C serial EEPROM 24C16

    Hardware & Software Tools

    To use, program and download, you need to provide the following hardware circuits and components are : -

    • ATMEL AT89C2051 Microcontroller chip,
    • provide a regulated +5V DC voltage supply by using a 78L05 or 7805 voltage regulator
    • DC jack, and any 12VDC Wall plug adapters
    • You can purchase a Low-Cost 89C2051 Programmer from our site PICPAK , a programmer that used to write HEX code to the chip or you can build it yourself Here's one FREE Programmer
    • Next, you need to obtain a C Compiler. The above program uses the KEIL C Compiler ( You can obtain a FREE download of thier demo 2K version fromDEMO KEIL C (2K ) However you can obtain a relatively Low Cost Professional SPJ C Compiler from INDIA SPJ 8052 C

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