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New technology products such as LED display screens are becoming increasingly popular, with higher usage rates both indoors and outdoors.
So what is the working principle of LED display screen? Lets tell all information about it to you.
Scanning mode
In the row scanning mode, each LED dot matrix chip has a set of column driver circuits.
There must be a latch or shift register in column driver circuit to latch font data of the content to be displayed.
In the row scanning mode, row control pins of same row of LED dot matrix chips with same name are connected in parallel to a line, a total of 8 lines, and finally connected to a row drive circuit, there must also be a row drive circuit Latch or shift register, used to latch the line scan signal.
Column drive circuit and row drive circuit of LED display screen are generally controlled by microcontrollers. Commonly used microcontroller is MCS51 series. Content displayed on LED display is generally stored in external data memory of microcontroller in the form of fonts, which are 8-bit binary numbers.
Scanning control of LED display screen by microcontroller
Control process of LED display screen by microcontroller is to read first and then write.
According to the order in which LED dot matrix slices are arranged onscreen, microcontroller first writes font data read from external data memory to column driver latch of the first LED dot matrix slice in first row, and then writes font data to the second LED dot matrix slice. , the third slice… until the last slice of this row has written font data, microcontroller then writes row scan signal to row drive latch of this row, so first row of first row emits light related to font data. The diode lights up. Then 1st row of the 2nd row, the 1st row of the 3rd row…until the 1st row of the last row lights up.
After the first row of each row is lit, there is a delay for a period of time, and then the screen goes black.
In this way, single-chip microcomputer’s one-row scanning control of LED display is completed.
Complete display of one frame of picture
Microcontroller controls scanning of second row of LED display, scanning control of third row… and the scanning control of eighth row.
Process is the same as scanning control process of the first row.
After control process of all 8 lines is completed, LED display screen will complete the complete display of one frame of picture.
Although according to this working method, the LED display is lit row by row, and only one row is lit at a time, as long as each row can be lit more than 50 times per second, that is, the refresh frequency is higher than 50 Hz, then due to human Due to the visual inertia, the picture displayed on LED display is still a full-screen, stable picture.
Conclusion
Above is detailed working principle of LED display screen.
If you have any other question, just contact us to inquire more.