Experimental description of the LED display technology directly drives the LED display technology using the microcontroller IO parallel port

Experimental task As shown, P0.0-P0.7 of the AT89S51 single-chip P0 port is connected to a pen section of a common coil digital tube A-H, the common end of the digital tube is grounded. The 0-9 digits are circulated on the digital tube, and the time interval is 0.2 seconds. 2. Circuit Schematic Figure 4.7.1 3. System board hardware connection Connect the P0.0 / AD0-P0.7 / AD7 port in the "MCU system" area to the A-H port of any of the digital tube in the "four-way static digital display module" area; : P0.0 / AD0 is connected to A, P0.1 / AD1 is connected to B, P0.2 / AD2 is connected to C, ..., P0.7 / AD7 is connected to H. 4. Program design content (1. LED digital display principle The seven-stage LED display is composed of seven strip-shaped light-emitting diodes and a small dot light-emitting diode, and can be divided into a common cathode type and a common male polar type according to the wiring form of the pole tube of each tube. The LED digital tube G ~ a seven light-emitting diodes are litter due to the electric voltage, and the different brightening combination can be formed, and the different brightening combination can form different glyphs. This combination is called a graphic code. The shape code given below is shown in Table 2. "0" 3FH "8" 7FH "1" 06h "9" 6FH "2" 5bh "a" 77h "3" 4FH "b" 7ch "4" 66h "c" 39h "5" 6DH "D" 5EH "6" 7DH "e" 79h "7" 07h "f" 71h (2. Since the word 0-9 displayed is not ruled, it can only be used to complete the requirements of our desired way. So we press the number 0-9, put each number The pen section is rinsed in order! The created form is as follows: TableDB3FH, 06H, 5BH, 4FH, 66H, 6DH, 7DH, 07H, 7FH, 6FH 5. Block diagram Figure 4.7.2 6. Assembly source ORG 0 Start: MOV R1, # 00H NEXT: MOV A, R1 Mov dptr, # TABLE MOVC A, @ a + dptr MOV P0, A LCALL DELAY INC R1 CJNE R1, # 10, Next LJMP START DELAY: MOV R5, # 20 D2: MOV R6, # 20 D1: MOV R7, # 248 DJNZ R7, $ Djnz R6, D1 DJNZ R5, D2 RET Table: DB 3FH, 06H, 5BH, 4FH, 66H, 6DH, 7DH, 07H, 7FH, 6FH End 7. C language source program #include "AT89X51.H" Unsigned char code Table [] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f}; UNSIGNED Char Dispcount; Void delay02s (void) { Unsigned Char i, J, K; For (i = 20; i "0; I -) For (j = 20; J "0; J -) FOR (k = 248; k "0; k -); } Void main (void) { While (1) { For (Dispcount = 0; Dispcount "10; Dispcount ++) { P0 = Table [Dispcount]; DELAY02S (); } } }, Read the full text

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