LED display is a display composed of light-emitting diodes. There are two kinds of composition: one is stroke character type, and there are generally three kinds: 7-segment (/8-segment) digital tube, 15-segment (/17-segment) digital tube and 6-segment symbol display; Followed by some dot matrix characters, such as 5×7, 5×8, 8×8, 16× 16. In order to meet the needs of different circuits, there are two forms of * * * cathode and * * * anode according to the polarity of the male * * pole of the light emitting diode that constitutes the LED display screen. For * * * cathode digital tube, the anode * * cathode is grounded. When the level on the anode of each part is high, the part is turned on, and when the level is 0, the part is turned off. For * * * anode digital tube, on the contrary, the high level is not bright, and the low level is bright. According to the number of display bits, the device can be divided into one-bit, two-bit and multi-bit LED displays. One-digit led display screen is called LED digital tube, and more than two-digit LED display screens are generally called LED display screens.

In order to realize Chinese character display of LED, it is necessary to supply power while scanning columns, because the luminous current of each row of 16 diodes is very large, and the output current of ordinary chips is far from satisfying. Here are some examples for your reference.

Taking 16× 16 display as an example, the parallel expansion chip 8255 can be used to realize the row scanning of dot matrix, and 8255 can expand an 8-bit parallel I/O port of single chip microcomputer to 16 bit (the PA port and PB port of 8255 can be used at the same time); The 16 bit of column scanning can be connected to two TTL gates 74LS 164(8-bit shift register), and 74LS 164 is connected to ULN2803 to amplify the current and then connected to 16× 16 grid. The shift trigger terminals A and B of 74LS 164 can be connected to the adjacent output terminals of one chip, and Q 1 Q7 can realize the continuous shift of multiple chips, thus realizing the function of moving Chinese characters from right to left or from left to right on the display screen.

Because Baidu knows that pictures can't be inserted, it doesn't provide pictures. Let me tell you the specific pin connection method: the data input terminal of D0-D7 of 8255 is connected to P2.0-P2.7 (any parallel I/O port), A0 is connected to P2.0, A 1 P2. 1, /wr is connected to /WR, /RD of single chip microcomputer. The trigger terminals A and B of the 74LS 164 chip are connected together, and are connected to the I/O of the single chip microcomputer at will with CK pin and CLK pin.