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Making an LED Blink - 2051

Step 1.) The first step is to build the circuit. At this point you should be familiar with the parts used. (2 resistors, 3 capacitors, 1 LED). You can either put these parts together using a breadboard or wirewrap. This design is intended for use with an Atmel 2051 microcontroller (a 20 pin version of the 8051). Most microcontrollers (such as a normal 8051 or 8751) can not handle the current required to turn an LED on and off but the ATMEL part has this capability.

After building the circuit you should have something that looks like the picture below (click the picture for a really big version!)

The only thing we want to do with this project is to make the LED blink. By doing this, you will be able to learn the basic process of compiling a program written in assembly language and then programming the resulting file into the microcontroller.

First we will assume we already have the assembly code written. ledtest.asm is the assembly language program we are going to use. (This file is included with TASM )

Step 2.) Compiling the Code

Move the assembly language program (ledtest.asm) to the directory where you have TASM. Bring up a DOS prompt, change to the directory where the TASM files are, and compile the code using the command

tasm -51 ledtest.asm ledtest.hex

This will create a file called ledtest.hex.

Close the DOS prompt window now.

Step 3.) Downloading the code to the Microcontroller.

Make sure the serial cable and the power supply are connected to the PG302 programmer.

Put your microcontroller into the PG302 programmer.

Run PG302.

From the Setup Menu, select the type of device (microcontroller) you are using

From the Setup Menu, select the Comm port you are using.

Press PROGRAM DEVICE.

Press BROWSE.

Find ledtest.hex and click on it (single click).

Press OK to select the file.

Press OK to program the file into the microcontroller.

Now the program should be loaded into the microcontroller.

Make sure the power is off for the circuit you have built.

Move the microcontroller back to the circuit you have built.

Turn on the power to the circuit. If the LED starts blinking, then you have successfully built your first microcontroller project.

The parts for this kit are included in the Microcontroller Beginner Kit. See part 2 for parts list.

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