Two display mode of full color screen

(1)static display

Static display is when a full-color LED screen display character,two forms o the corresponding led beads will come out, constant conduction and constant.This kind of display requires all board constant ground (common cathode) or the power (anode).Each display pieces of eight period of line selection and an 8-bit parallel I/O port of eight mouth into the line, I/O mouth as long as there is a section of code output, namely the instructions of the corresponding characters, and maintain a small change, until I/O output a new piece of code.
   When adopt static display mode,lower current can get high brightness,and it occupy less time,easier to programme,but because every LED screen need to equipped with collateral output,then take up a lot of I/O port resources,and its hardware will get high cost,thus it is better not adopt this display mode when need to display large display digits.

(2)Dynamic display

Dynamic display refers to one by one take turns to display every LED display board.we called this position scan.and this display mode require that monitor section of line selection is connected in parallel, mainly by a 8 bits of I/O control;While each bit line selection is controlled by the other I/O port line.
The way at the time of display, each in turn display gate, to make it, according to the stability of it is necessary to adopt the way of scanning, that is to say, at some point, we choose a display, and send than the corresponding section of code, proper time delay (probably will delay time is about 1-5 ms), and then choose another display, and the corresponding section of the code will be sent, so cycle, can make full color LED display of the display shows the corresponding characters.
If you can guarantee the cycle time short enough, we can use the human eye persistence of vision effect, to give a person a kind of display.