Full color LED display of the two display
(1) static display mode
The so-called static display, it refers to when the full-color LED display shows a character when the corresponding light-emitting diodes will appear constant conduction or constant cut off two forms. This display mode requires that the common side of the display block be permanently grounded (common cathode) or the positive supply (common anode). The 8 segments of each display block are respectively connected with the 8-bit line of an 8-bit parallel I / O port. The I / O port is outputted as long as the segment is output, and the corresponding characters are marked and remain small until I / O output new segment code.
We use a static display of the time, the smaller the current can be very high brightness, and it takes less CPU time, programming is also very easy, but, because each LED display should be Equipped with a parallel output port, which takes up a lot of I / O port resources, so that its hardware costs become high, so that when the display bit is better, do not use this approach.
(2) dynamic display mode
For the dynamic display of the way, it is a one by one in turn to light up the display, according to this by way of light-like display is called the bit scan. And this display means that the display of the section of the monitor line is connected in parallel, mainly by an 8-bit I / O port control; and you bit line by the other I / O line control. The way in the display, the display turns alternately, to make it stable display, it must be used to scan the way, that is, at a time, we only pass a monitor, and send the corresponding (For example, the delay time is about 1-5ms), then another other display, and will send the corresponding segment code, so the cycle, then you can make full-color LED display The display of the screen shows the corresponding characters. If we can ensure that the cycle time is short enough, we can use the visual effect of the human eye to achieve a sense of giving a display.