STM32 controls the output count of 4-bit common anode digital tube

A total of 12 pins of GPIO port PA0~PA11 are used

First, the schematic diagram

Because it is a common anode, 12, 9, 8, and 6 are power inputs, and the other pins are grounded. So for the chip, 12, 9, 8, and 6 are high outputs, and the others can be set to low.

1. //Set the GPIO port  

2. void GPIO_Num_Init(void)  

3. {  

4.     GPIO_InitTypeDef GPIO_InitStructure;  

5.     RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);  

6.     GPIO_PinRemapConfig(GPIO_Remap_SWJ_Disable, ENABLE);  

7.   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;  

8.     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;   

9.     GPIO_InitStructure.GPIO_Speed ​​= GPIO_Speed_50MHz;  

10.     GPIO_Init(GPIOA,&GPIO_InitStructure);  

11. }  

There is one thing to note here. According to the schematic diagram, the digital tube can only output one bit of array at a time, so if it is multi-bit, it must be output in a scanning manner. By shortening the switching interval, a non-flickering effect can be achieved.

1. //Output package  

2. void DisPlayNum(int n)  

3. {  

4.     if (n < 9999)  

5.     { int i;  

6.         int s;    

7.         s = n;  

8.         i=0;  

9.         for (i=0;i<4;i++)  

10.         {  

11.             GPIO_ResetBits(GPIOA,GPIO_Pin_All);  

12.             switch (i)  

13.             {  

14.                                 case 0:  

15.                     GPIO_SetBits(GPIOA,GPIO_Pin_5);  

16.                     break;  

17.                 case 1:  

18.                     GPIO_SetBits(GPIOA,GPIO_Pin_7);  

19.                     break;  

20.                 case 2:  

21.                     GPIO_SetBits(GPIOA,GPIO_Pin_8);  

22.                     break;  

23.                 case 3:  

24.                     GPIO_SetBits(GPIOA,GPIO_Pin_11);  

25.                     break;  

26.                         }  

27.           

28.             switch (s % 10)  

29.             {  

30.                 case 0:  

31.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_4);   

32.                     break;  

33.                 case 1:  

34.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_4|GPIO_Pin_9|GPIO_Pin_10);  

35.                     break;  

36.                 case 2:  

37.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_9);  

38.                     break;  

39.                 case 3:  

40.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_0|GPIO_Pin_9);  

41.                     break;  

42.                 case 4:  

43.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_10);  

44.                     break;  

45.                 case 5:  

46.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_0|GPIO_Pin_6);  

47.                     break;  

48.                 case 6:  

49.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_6);  

50.                     break;  

51.                 case 7:  

52.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_4|GPIO_Pin_9);  

53.                     break;  

54.                 case 8:  

55.                     GPIO_SetBits(GPIOA,GPIO_Pin_2);  

56.                     break;  

57.                 case 9:  

58.                     GPIO_SetBits(GPIOA,GPIO_Pin_2|GPIO_Pin_0);  

59.                     break;  

60.             }     

61.             s = s / 10;  

62.             delay_ms(1);  

63.             if (s==0)  

64.                 break;  

65.         }      

66.     }  

67. }  

Finally, the main test code

1. int count;  

2. int TimeCheck;  

3.   

4. int main(void)  

5. {  

6.     GPIO_Num_Init();  

7.     count =0;  

8.     TimeCheck = 0;  

9.     while(1)  

10.     {  

11.         DisPlayNum(count);  

12.         TimeCheck++;  

13.         delay_ms(5);  

14.         if (TimeCheck > 100){ //+1 every 500 milliseconds  

15.             TimeCheck=0;  

16.             count++;  

17.         }  

18.     }  

19. }