51 MCU Introduction 4: Static Digital Tube

LED digital tube is a commonly used display device in the peripheral interface device of single-chip microcomputer. There are two types of display devices, seven-segment tube and Mi tube. The seven-segment tube is commonly used in the laboratory. There are two working modes: common cathode and common anode. The so-called common cathode is to connect the com end of the LED to the ground, and the common anode is to connect the com end to a high level. There are also two driving display modes: static display and dynamic display.

In static display, each digital tube occupies an eight-bit I/O port of the microcontroller, and the lit segment is always on during operation. In this way, the hardware circuit is simple, the programming is simple, but the I/O port of the microcontroller is wasted. The following is a brief demonstration of this driving method.

Connect a digital tube to port P2. The number displayed on the digital tube will automatically increase by one every second, and will be cleared to 0 after adding to 9, and the cycle will continue. In this experiment, the digital tube adopts the common cathode connection method.

The experimental principle diagram is as follows:

The experimental procedure is as follows:

[cpp]  view plain  copy

1. #include  

2. #define uchar unsigned char;  

3. #define uint unsigned int;  

4. uchar code table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f}; //Common cathode digital tube data table  

5. uchar a,i,j,z;  

6.   

7. void delay(z) //delay sub-function  

8. {  

9.    for(j=z;j>0;j--)  

10.       for(i=110;i>0;i--);  

11. }  

12.   

13. void main() //Main function  

14. {  

15.   while(1)  

16.     {  

17. for(a=0;a<10;a++) //From 0 to 9, a total of 10 cycles     

18.      {  

19.      P2=table[a]; //P2 port gets data from the data table  

20.      delay(1000); //delay about 1s   

21.       }        

22.     }  

23. }  

The test results are as follows: