Question

Design a circuit using PIC 18F458, which counts the number of input pluses read by any input I/O port of the PIC 18 and show the pulses counting state on the 7-segment display. Hint: For Input pulses function generator or 555 Astable oscillator can be used.

Answer 1

Coding for the designing of 7 segment display in pic18f458 is provided by me, which will give your the required results easily. -

Data lines for all SSD's are common. and they are connected to PORTD.
To select particular SSD of that Bank we have used another latch(latch 6) connected to PORTE = E0 bit

if I want to select SSD no. 2 and SSD no 10 then steps needed are as follows
PORTA - A1 =1 //Enable bank 1
PORTD - D6 = 0 //Select SSD 2 by making D6 bit low.
PORTE - E0 = 1 //Enable PORTE to load value of PORTD(in this case D6) and select that SSD.
  
PORTD= 0xFF // Send character FF to SSD 2
  
PORTA - A2=1 //Enable bank 2
PORTD - D5 = 0 // Select SSD 10 by making D5 pin low
PORTE - E0 = 1 //Enable PORTE to load value of PORTD(in this case D5) and select that SSD.
  
PORTD - D = 0xFE // Send Character FE to SSD 10.

code for the same :-

#include <p18f4550.h>

#pragma config FOSC         =    HS     // 20MHz Crystal, (HS oscillator)
#pragma config PBADEN      =    OFF // PORTB<4:0> pins are configured as digital I/O on Reset)
#pragma config WDT         =    OFF // watch dog timer off
#pragma config LVP         =    OFF // Low voltage program off


void main()
{    
     ADCON1 = 0xFF;                                    // Configure all ports with analog function as digital
     CMCON = 7;
     TRISD=0;    //make PORTD all out put
     TRISB=0xf0; //make PORTB pins 0:4 o/p and others input( we need only 0:4 pins)
     TRISA=0;
     TRISE=0;

     while(1)
     {
     PORTA=0x02; //Enable bank_1
     PORTD=0xBF; //Select SSD 2 by making D6 bit low.
     PORTE=0x01; //Enable PORTE to load value of PORTD(in this case D6) and select that SSD.
     PORTE=0x00;    //Disable PORT E so that character data won't go in SSD Select latch, i.e=PORTE - E0 bit.

     PORTD= 0xFF // Send character FF to SSD 2

     PORTA=0x04; //Enable bank_2
     PORTD=0xDF;    // Select SSD 10 by making D5 pin low
     PORTE=0x01; //Enable PORTE to load value of PORTD(in this case D5) and select that SSD.
     PORTE=0x00;    //Disable PORT E so that character data won't go in SSD Select latch, i.e=PORTE - E0 bit.

     PORTD=0xFE; // Send Character FE to SSD 10.
     }

}