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
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.
The Table-11 below gives the logic levels to be applied to R1 through R7 for each of the columns in order to display the alphabet ‘A’.
By these techniques we will display the Character 'A' in the 5x7 Led Dot Matrix Display and it is look like as below;
[2] Column Scanning Method
[2]
Column Scanning Method
Suppose we want to display the alphabet
A in the common anode 5x7 led dot matrix segment. We will first select the
column C1 (which means C1 is pulled low in this case), and deselect other
columns by blocking their ground paths (one way of doing that is by pulling C2
through C5 pins to logic high).
Now, the first column is active, and you need to turn on the LEDs in the rows R2 through R7 of this column, which can be done by applying forward bias voltages to these rows. Next, select the column C2 (and deselect all other columns), and apply forward bias to R1 and R5, and so on.
Now, the first column is active, and you need to turn on the LEDs in the rows R2 through R7 of this column, which can be done by applying forward bias voltages to these rows. Next, select the column C2 (and deselect all other columns), and apply forward bias to R1 and R5, 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.
Row/Col
|
C1
|
C2
|
C3
|
C4
|
C5
|
R1
|
0
|
1
|
1
|
1
|
0
|
R2
|
1
|
0
|
0
|
0
|
1
|
R3
|
1
|
0
|
0
|
0
|
1
|
R4
|
1
|
0
|
0
|
0
|
1
|
R5
|
1
|
1
|
1
|
1
|
1
|
R6
|
1
|
0
|
0
|
0
|
1
|
R7
|
1
|
0
|
0
|
0
|
1
|
Table-11
The Table-11 below gives the logic levels to be applied to R1 through R7 for each of the columns in order to display the alphabet ‘A’.
Fig.11a
By these techniques we will display the Character 'A' in the 5x7 Led Dot Matrix Display and it is look like as below;
Fig.11b
The End....
Also visit Post-10 to get idea about How Row Scanning Method is working in the LED Dot Matrix Display......
God Bless Thx........
