Problem regarding the code that I made for my PIC16F627A microcontroller

The comments have addressed the OPs immediate issue.

There are a few other issues that the OP should consider:

• Only some of the configuration bits are initialized.
• The watch dog timer is enabled but not reset in the code.
• The interrupts are not explicitly disabled
• The analog inputs for the comparators are not explicitly disabled

This code is more complete:

/* * File: main.S * Target: PIC16F627A * Author: dan1138 * Date: 2024-05-14 * Compiler: XC8 v2.45 * IDE: MPLABX v6.00 * * Description: * * Answer for homework see: https://electronics.stackexchange.com/questions/713282/problem-regarding-the-code-that-i-made-for-my-pic16f627a-microcontroller * * PIC16F627A * +----------:_:----------+ * SW2 <> 1 : RA2 RA1 : 18 <> SW1 * SW3 <> 2 : RA3 RA0 : 17 <> SW0 * SW4 <> 3 : RA4(*) OSC1/RA7 : 16 <> * VPP -> 4 : RA5/MCLRn OSC2/RA6 : 15 <> * GND -> 5 : VSS VDD : 14 <- 5v0 * LED0 <> 6 : RB0 PGD/RB7 : 13 <> /PGD * LED1 <> 7 : RB1/RX/DT PGC/RB6 : 12 <> /PGC * LED2 <> 8 : RB2/RX/CK RB5 : 11 <> * LED3 <> 9 : RB3/CCP1 PGM/RB4 : 10 <> LED4 * +-----------------------: * DIP-18 * Notes: * (*) RA4 is an open drain output. Requires an external pull-up for output. * * Created on May 17, 2024, 1:01 PM */ /* * Define the system oscillator frequency this code will setup */ #define _XTAL_FREQ 4000000 // PIC16F627A Configuration Bit Settings // CONFIG #pragma config FOSC = INTOSCIO // Oscillator Selection bits (INTOSC oscillator: I/O function on RA6/OSC2/CLKOUT pin, I/O function on RA7/OSC1/CLKIN) #pragma config WDTE = OFF // Watchdog Timer Enable bit (WDT disabled) #pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled) #pragma config MCLRE = ON // RA5/MCLR/VPP Pin Function Select bit (RA5/MCLR/VPP pin function is MCLR) #pragma config BOREN = OFF // Brown-out Detect Enable bit (BOD disabled) #pragma config LVP = OFF // Low-Voltage Programming Enable bit (RB4/PGM pin has digital I/O function, HV on MCLR must be used for programming) #pragma config CPD = OFF // Data EE Memory Code Protection bit (Data memory code protection off) #pragma config CP = OFF // Flash Program Memory Code Protection bit (Code protection off) #include <xc.h> void main (void) { INTCON = 0; /* disable interrupts */ CMCON = 0x07; /* turn off comparator analog inputs */ TRISAbits.TRISA0 = 1; // Set RA0 as input TRISAbits.TRISA1 = 1; // Set RA1 as input TRISAbits.TRISA2 = 1; // Set RA2 as input TRISAbits.TRISA3 = 1; // Set RA3 as input TRISAbits.TRISA4 = 1; // Set RA4 as input TRISBbits.TRISB0 = 0; // Set RB0 as output TRISBbits.TRISB1 = 0; // Set RB1 as output TRISBbits.TRISB2 = 0; // Set RB2 as output TRISBbits.TRISB3 = 0; // Set RB3 as output TRISBbits.TRISB4 = 0; // Set RB4 as output PORTBbits.RB0 = 0; // Initialize RB0 to zero PORTBbits.RB1 = 0; // Initialize RB1 to zero PORTBbits.RB2 = 0; // Initialize RB2 to zero PORTBbits.RB3 = 0; // Initialize RB3 to zero PORTBbits.RB4 = 0; // Initialize RB4 to zero PORTA = PORTB; while(1) { if(PORTAbits.RA0 == 1) { // Blink at 100 ms flash rate with 400 ms gap PORTBbits.RB0 = 1; // Toggle RB0 __delay_ms(200); // Flash rate PORTBbits.RB0 = 0; __delay_ms(200); // Gap PORTBbits.RB0 = 1; // Toggle RB0 __delay_ms(200); // Flash rate PORTBbits.RB0 = 0; __delay_ms(200); // Gap } if(PORTAbits.RA1 == 1) { // Blink at 30 ms flash rate with 30 ms gap PORTBbits.RB1 = 1; // Toggle RB0 __delay_ms(200); // Flash rate PORTBbits.RB1 = 0; __delay_ms(200); // Gap PORTBbits.RB1 = 1; // Toggle RB0 __delay_ms(200); // Flash rate PORTBbits.RB1 = 0; __delay_ms(200); // Gap } if(PORTAbits.RA2 == 1) { // Blink at 100 ms flash rate with 500 ms gap PORTBbits.RB2 = 1; // Toggle RB0 __delay_ms(300); // Flash rate PORTBbits.RB2 = 0; __delay_ms(300); // Gap PORTBbits.RB2 = 1; // Toggle RB0 __delay_ms(300); // Flash rate PORTBbits.RB2 = 0; __delay_ms(300); // Gap } if(PORTAbits.RA3 == 1) { // Blink at 100 ms flash rate with 500 ms gap PORTBbits.RB3 = 1; // Toggle RB0 __delay_ms(500); // Flash rate PORTBbits.RB3 = 0; __delay_ms(500); // Gap PORTBbits.RB3 = 1; // Toggle RB0 __delay_ms(500); // Flash rate PORTBbits.RB3 = 0; __delay_ms(500); // Gap } if(PORTAbits.RA4 == 1) { // Blink at 100 ms flash rate with 500 ms gap PORTBbits.RB4 = 1; // Toggle RB0 __delay_ms(500); // Flash rate PORTBbits.RB4 = 0; __delay_ms(500); // Gap PORTBbits.RB4 = 1; // Toggle RB0 __delay_ms(500); // Flash rate PORTBbits.RB4 = 0; __delay_ms(500); // Gap } } } 

This homework assignment may be more involved than the OP has described. My suspicion is that the LEDs are supposed to all flash at different rates when each switch is asserted rather than just one at a time. Note that the code as posted does not do this.