I am trying to write an assembly code for my Microcontrollers Class.

Here is the assignment:
Make a program that converts a 4-bit binary number in one hexadecimal number (0-F).
The output value must be presented in a 7-segment display and an LCD at the same time.

Here is the Beginning of the code I already started

PROCESSOR  16F877A
#include <p16f877a.inc>    ; incluir arquivo

    __CONFIG _CP_OFF & _WDT_OFF & _PWRTE_ON & _XT_OSC
   
    contador EQU 0X20

ORG 0x00

    org  0x00            ;  reset vector
    goto Main          ;
           
    org  0x04            ; interruption vector
    goto Main          ; don't has interruption routine


Main                
;--------------------------------------------;
;                 7-segments                            ;
;--------------------------------------------;
    BSF STATUS,5   
    MOVLW B'00001111'
    MOVWF ADCON1
    MOVLW B'00001111'
    MOVWF TRISA
    MOVLW B'00000000'
    MOVWF TRISB
    bcf STATUS,5
    clrf PORTB

;--------------------------------------------;
;                    LCD                     ;
;--------------------------------------------;
BCF STATUS,RP1 ; select bank 1
BSF STATUS,RP0
CLRF TRISB ; bank b as output (LCD)
CLRF TRISD ; port d as output (RD0-R/S, RD1-E)

MOVLW b'00000111'
MOVWF OPTION_REG ; Configuração do registrador OPTION_REG para TMR0  1:256

BCF STATUS,RP0 ; select bank 0
CLRF PORTB ;
CLRF PORTD ;

CALL InicializaLCD

LOOP2
CALL CONVERTEBINPHEX
GOTO LOOP2


;-------------------------------------------;
REINICIO
        clrf contador
        ;clrf PORTA
IMPRIME
        MOVF PORTA,w   ; read  in A 4 bits.
        movf contador,w
        CALL tabela
        movwf PORTB
    
        incf contador, f ; +1 on table
        movlw d'16' ;
        xorwf contador
       
        BTFSS STATUS,Z
        goto IMPRIME  ; z=0  a xor /=0, isso significa que o contador não chegou a 16 posições da tabela
        goto REINICIO ; z=1   a xor = 0, isso significa que o contador  chegou a 16 posições da tabela e inicia novamente a tabela.

tabela
    ADDWF PCL,f    ;
    RETLW B'11111100' ; imprime 0
    RETLW B'01100000' ; imprime 1
    RETLW B'11011010' ; imprime 2
    RETLW B'11110010' ; imprime 3
    RETLW B'01100110' ; imprime 4
    RETLW B'10110110' ; imprime 5
    RETLW B'11111010' ; imprime 6
    RETLW B'11100000' ; imprime 7
    RETLW B'11111110' ; imprime 8
    RETLW B'11100110' ; imprime 9
    RETLW B'11101110' ; imprime A
    RETLW B'11111111' ; imprime B        
    RETLW B'11110000' ; imprime C
    RETLW B'11111101' ; imprime D
    RETLW B'10011110' ; imprime E
    RETLW B'10001110' ; imprime F


;tempo1s



;////////////////////////////////////////////////////////////////////////////////////////////////////

InicializaLCD
BCF PORTD,RD0 ; Define RS como 0 para enviar comandos ao LCD
CALL DELAY_5ms

MOVLW b'00000001' ; clean display
MOVWF PORTB
CALL Enable
CALL DELAY_5ms

MOVLW b'00111000' ;
MOVWF PORTB
CALL Enable
CALL DELAY_5ms

MOVLW b'00001111' ; Display on off
MOVWF PORTB
CALL Enable
CALL DELAY_5ms

MOVLW b'00000110' ;
MOVWF PORTB
CALL Enable
CALL DELAY_5ms

RETURN

EscreveCaracter

BCF PORTD,RD0 ; Define RS as 0 to sent enviar data to LCD
MOVLW b'00000001' ; Set home cursor
CALL Escreve

MOVLW b'00000010' ; Set  home cursor
CALL Escreve

BSF PORTD,RD0 ; Define RS as 1 to sent data to LCD
CALL DELAY_5ms

    BCF STATUS,RP1   ;select bank 1
    BSF STATUS,RP0
    CLRF TRISB       ;port b as output (LCD)
    CLRF TRISD       ;port d as output (RD0-R/S, RD1-E)
     MOVLW b'00000111'
     MOVWF OPTION_REG    ;Configuração do registrador OPTION_REG para TMR0  1:256
    BCF STATUS,RP0               ;Select bank 0
    CLRF PORTB      
    CLRF PORTD      

CALL InicializaLCD

LOOP2
CALL CONVERTEBINPHEX
GOTO LOOP0
;-------------------------------------------------------------------;

CONVERTEBINPHEX

table
    ADDWF PCL,f    ;
    RETLW B'00000000' ; print 0
    RETLW B'00000001' ; print 1
    RETLW B'00000010' ; print 2
    RETLW B'00000011' ; print 3
    RETLW B'00000100' ; print 4
    RETLW B'00000101' ; print 5
    RETLW B'00000110' ; print 6
    RETLW B'00000111' ; print 7
    RETLW B'00001000' ; print 8
    RETLW B'00001001' ; print 9
    RETLW B'00001010' ; print A
    RETLW B'00001011' ; print B       
    RETLW B'00001100' ; print C
    RETLW B'00001101' ; print D
    RETLW B'00001110' ; print E
    RETLW B'00001111' ; print  F

END

; IDK if the order is correct, or something link that, but I know something is missing, can you help?

Moderator edit: code tags added like this [code]your code...[/code]

 

One avenue for numeric conversion code is the PicList site.
Also Nigel Goodwin Tutorials.

 

Even for something basic as it is, I would prepare a flow diagram first so writing code becomes just a clerical work.