Interfacing PIC12F1822 with 7-segment display circuit:
Here is an example shows how to make a digital up counter where the number is displayed on a 7-segment display uses multiplexing technique with shift register.
Example circuit schematic is shown below where a common anode 7-segment display and 74HC164N shift register are used.
Other shift registers such as 74HC595 or CD4094 can be used in this project.
The displayed number can be incremented using a push button connected to RA3 pin.
Internal oscillator of the PIC12F1822 microcontroller is used @ 8MHz and MCLR pin function is disabled.
The push button is connected to pin RA3. The shift register used in this example is 74HC164 but other types can work properly like 74HC595 or CD4094.
In this example all pins of PIC12F1822 are used and there is no free pin.
The PIC12F1822 microcontroller must be supplied with 5V between pins VDD (#1) and VSS (#8).
Interfacing PIC12F1822 with 7-segment display C code:
The C code below was tested with CCS C compiler version 5.051.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 | // Interfacing PIC12F1822 with 7-segment display // Common anode 7-segment display used #include <12F1822.h> #fuses NOMCLR INTRC_IO #use delay(clock=8000000) #use fast_io (a) short s; // Used to know button position unsigned int j, digit, digit1, digit10, digit100; unsigned long i = 0; unsigned int seg(unsigned int num) { switch (num) { case 0 : return 0xC0; case 1 : return 0xF9; case 2 : return 0xA4; case 3 : return 0xB0; case 4 : return 0x99; case 5 : return 0x92; case 6 : return 0x82; case 7 : return 0xF8; case 8 : return 0x80; case 9 : return 0x90; } } void main() { setup_oscillator(OSC_8MHZ); // Set internal oscillator to 8MHz set_tris_a(8); // Configure RA3 pin as input port_a_pullups(8); // Enable RA3 internal pull-up while(TRUE) { if(input(PIN_A3) == 1) s = 1; if(s == 1) { if(input(PIN_A3) == 0) { s = 0; i++; if(i > 999) i = 0; } } digit = i % 10; digit1 = seg(digit); output_a(7); // Turn off all displays for(j = 0x40; j > 0; j = j >> 1) { if(digit1 & j) output_high(PIN_A4); else output_low(PIN_A4); delay_us(10); output_high(PIN_A5); delay_us(10); output_low(PIN_A5);} output_low(PIN_A0); // Turn on display for ones delay_ms(1); digit = (i / 10) % 10; digit10 = seg(digit); output_a(7); // Turn off all displays for(j = 0x40; j > 0; j = j >> 1) { if((digit10 & j) != 0) output_high(PIN_A4); else output_low(PIN_A4); delay_us(10); output_high(PIN_A5); delay_us(10); output_low(PIN_A5);} output_low(PIN_A1); // Turn on display for tens delay_ms(1); digit = (i / 100) % 10; digit100 = seg(digit); output_a(7); // Turn off all displays for(j = 0x40; j > 0; j = j >> 1) { if((digit100 & j) != 0) output_high(PIN_A4); else output_low(PIN_A4); delay_us(10); output_high(PIN_A5); delay_us(10); output_low(PIN_A5);} output_low(PIN_A2); // Turn on display for hundreds delay_ms(1); } } |
Interfacing PIC12F1822 with 7-segment display video:
The following video shows project in a hardware circuit with some details.
