It's here!
Out Now!
EdSim51 Version 2 has Arrived.

Introducing EdSim51DI.

Find out more Read sample chapter

The textbook by
James Rogers, creator of EdSim51,
is now available.

EdSim51 The 8051 Simulator for
Teachers and Students

Home Prefer the
About the


Examples Contact
The Fundamental
Site Map
Developed by James Rogers -

Check out EdSim51's

Create Your Own Target Board

Back by popular demand - EdSim51SH

Text windows in the External UART too small?
Now you can unlock the UART.

Simulate Your C Code in EdSim51

Import Embedded C using
the Intel HEX reader/writer.

Syntax Highlighting

Change the System Frequency

Type in a Value for Update Freq.

UART Transmitting HEX Data

The LCD Module with CGRAM


Keypad Modes and Interrupt


Source Pane Unlocker

 Get the EdSim51DITM Simulator now, FREE!  *

version number: 2.1.21

For information on downloading and installing EdSim51,
go to the Installation Instructions.

An update to Java caused a problem with rendering the logic diagram in EdSim51DI. This has been fixed in version 2.1.21.

Having trouble with EdSim51 in Windows 7/8?
Your JAR files may have been hijaked. Fix it.
Get the book that goes with EdSim51, written by EdSim51's creator.

Do you want to learn about microcontrollers and embedded systems?

Are you studying the 8051 microcontroller?

Do you want to test your code for communicating with
peripherals without having to first build the hardware?

Are you teaching an embedded systems course and would
like your students to have access to a virtual 8051 training kit?

If the answer to any or all of the above is true,
then you've come to the right place.
The EdSim51 Simulator for the popular 8051 microcontroller
is exactly the tool you need.
And it's FREE!

A virtual 8051 is interfaced with virtual peripherals such as a keypad,
motor, display, UART, etc.

The student can write 8051 assembly code, step through the code and observe
the effects each line has on the internal memory and the external peripherals.

Like EdSim51?
Consider donating to UNICEF

or to the charity of your choice.


The screenshot below shows the simulator in action. | full-size image

The Virtual Peripherals:
  • Analogue-to-Digital Converter (ADC)
  • Comparator
  • UART
  • 4 Multiplexed 7-segment Displays
  • 4 X 3 Keypad
  • 8 LEDs
  • DC Motor
  • 8 Switches
  • Digital-to-Analogue Converter (DAC) - displayed on oscilloscope
Why EdSim51's Simulator and not some of the many other simulators that are available?
Many of the simulators for the 8051 that you will find are industry-standard. They are used by professional 8051-based embedded systems designers. While they show the state of the registers, memory and the port pins while code is being debugged, they do not have graphical representations of peripherals that can be used interactively to communicate with the 8051. EdSim51 have filled that need.
The student can learn how to scan a keypad, multiplex 7-segment displays, control a motor and count its revolutions, etc.
Find out all about the simulator here: EdSim51's 8051 Simulator
Please send us your comments with feedback, suggestions or if you spot mistakes in either the simulator or the notes. Thank you.
Fixing the Windows 7 hijaking problem.
A number of Windows 7 users have reported problems with launching EdSim51. It seems Windows 7 may be hijaking JAR files. Johann N. Löfflmann has kindly provided a solution. Thanks to Ishwar Bhat for finding this solution.

Microcontroller Fundamentals Simulations
EdSim51 have also developed a browser-based simulation of three key microcontroller concepts:
  • Memory Read Cycle
  • Memory Write Cycle
  • Instruction Execution Cycle
These simulations require nothing more than a web browser such as Firefox or Internet Explorer.
Click on EdSim51's The Fundamentals Simulations.

EdSim51 is FREE
Copyright Notice:
EdSim51 and EdSim51DI are available free of charge.
No part of EdSim51 or EdSim51DI or their documentation may be sold for profit or included in a package that is sold for profit without written authorisation from James Rogers.

Home Prefer the
About the


Examples Contact
The Fundamental
Site Map

Copyright (c) 2005-2016 James Rogers