51 MCU Programming Section 4: Digital Tube Driver

1. #include    

2. unsigned char DisBuf[8]; //Global display buffer, DisBuf[0] corresponds to the right SLED, DisBuf[7] corresponds to the left SLED,   

3. void DisplayBrush(void)   

4. { code unsigned char cathode[8]={0xfe,0xfd,0xfb,0xf7,0xef,0xdf,0xbf,0x7f}; // cathode control code   

5. Code unsigned char Seg7Code[16]= //Use hexadecimal as the array subscript to directly obtain the corresponding seven-segment code bytes   

6. {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};   

7. static unsigned char i=0; // (0≤i≤7) Refresh the display in a loop. Since it is a static variable, this assignment is only done once.   

8. P2 = 0xff; //Display blanking to prevent the next code value from being displayed on the previous SLED   

9. P1 = Seg7Code[ DisBuf[i] ]; //Get the original data from the display buffer, convert it into seven-segment code after looking up the table, and then send it to the display   

10. P2 = cathode[ i ]; //Set the corresponding cathode to low and display   

11. if( ++i >= 8 ) i=0; //point to the next digital tube and corresponding data   

12. }   

13. void Timer0IntRoute( void ) interrupt 1   

14. {   

15. TL0 = -1000; //Since TL0 has only 8 bits, assign the lower 8 bits of (-1000) to TL0   

16. TH0 = (-1000)>>8; // Take the high 8 bits of (-1000) and assign them to TH0, re-timing 1ms   

17. DisplayBrush();   

18. }   

19. void Timer0Init( void )   

20. { TMOD=(TMOD & 0xf0) | 0x01; // Initialization, timer T0, working mode 1   

21. TL0 = -1000; // Timing 1ms   

22. TH0 = (-1000)>>8;   

23. TR0 = 1; //Allow T0 to start counting   

24. ET0 = 1; //Allow T0 to generate an interrupt request when the count overflows   

25. }   

26. void Display( unsigned char index, unsigned char dataValue ){ DisBuf[ index ] = dataValue; }   

27. void main( void )   

28. {   

29. unsigned char i;   

30. for( i=0; i<8; i++ ){ Display(i, 8-i); } //DisBuf[0] is right, DisBuf[7] is left   

31. Timer0Init();   

32. EA = 1; // Allow CPU to respond to interrupt requests   

33. While(1);   

34. }