Greb-A-Knowlegde: Create A Character With Row Scanning Method In The LED Dot Matrix Display

Basic use of Led dot Matrix Module is used to display character in different different way. For that, How to generate a character in this segment? This is simple and first question raises in our mind.

If we talking about the generating character in Module, we satisfied the law of “Persistence of Vision”. In that law, our eye is detect the static character when at a time 1/16 different frames are moving in the segments. It means that the character display on the segment it is not steady in that one but it is scanning rows or column in segments.

Way of Scanning Techniques

There are some useful techniques by which we can done software multiplexing in 5x7 Led Dot Matrix Module. These are classifying in two methods which names as follows:

[1] Row Scanning Method
[2] Column Scanning Method

[1] Row Scanning Method

Suppose we want to display the alphabet A in the common anode 5x7 led dot matrix segment. We will first select the row R1 (which means R1 is pulled high in this case), and deselect other rows by blocking their ground paths (one way of doing that is by pulling R2 through R7 pins to logic low).

Now, the first row is active, and you need to turn on the LEDs in the columns C2 through C4 of this column, which can be done by applying forward bias voltages to these columns. Next, select the row R2 (and deselect all other rows), and apply forward bias to C1 and C5, and so on.

Therefore, by scanning across the column quickly (> 100 times per second), and turning on the respective LEDs in each row of that column, the persistence of vision comes in to play, and we perceive the display image as still.