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LAB 2: Implementation of sign board
DOT matrix display with 8051
Implementation of dot-matrix led based system using MCS-51
To design the hardware to interface the display to MCS51 microcontroller.
To develop the application software using C language
To simulate the program and verify the result
This laboratory experiment will provide a basic concept on how to drive and
control a dot matrix led using 8051 microcontroller. An 8x8 dot matrix is selected for this
Dot matrix led display
Dot-matrix led display comprises of an array of LED’s that are intersected in such
a way that the negative terminal of each LED (cathode) in the same rows are connected
and the positive terminal (anode) of each LED in the same column are linked together.
Fig.1 internal structure an
LED dot matrix
The figure above shows the basic schematic for a typical 8x8 led matrix
The dot-matrix led displays are widely a used to display information on machines,
clocks, train station departure, airport and sign boards etc.
Choosing a microcontroller
When embarking on a dot-matrix display project or assignment, the main
consideration should focus on the type of microcontroller to use. The specification must
to be considered in selecting the microcontrollers are the number of I/O pins available,
the amount of current that each pin can source and finally the speed at which the
The 89c51 microcontroller has made the issue of control signal speed and I/O pins
availability. The chip has a total number of 32 I/O pins and operates at a speed greater
Design the hardware to interface display to the MCS-51 microcontroller.
In the hardware design, six 8x8 dot-matrix LEDs were used and 74HC595 used
for serial to parallel shift registering in order to use less I/O pins of the microcontroller.
By using the 74HC595, only 3 I/O lines to drive 8 LEDs. The below figure shows the
hardware design in proteus software.
The implementation of the microcontroller based sign board dot matrix led
display. There were many challenges face while doing this lab assignment. First
challenge was on how to display a single character on the dot-matrix, which was
achieved after a very long battle. The second challenge was scrolling the characters using
timer, it was also achieved over a very long battle where the second challenge was more
challenging than the first challenge. The finally challenge was how to display clock on
the dot-matrix led, and that was successful achieved.
Moreover, regarding the hardware implementation, a single dot matrix led was
used due to time and cost constrain.
Apparently, all the lab objectives were successfully achieved and all learned were
a. Mazidi.M.A., Mazidi J.G., 2000,“8051 Microcontroller and Embedded Systems”,Upper
Saddle River, N.J. Pearson Edu. Inc.
The hardware was implemented, a single dot matrix led was used due to time and