Using a PIC16C57 to control a LCD using assemby language

	list p=16C57
	org 0x00

	Call Setup; Sets up the ports and timer
	Call Int; Calls for the Initialzation sub rountine
	Call Enable; latchs the value
	Call IntTime; alows for the time delay to take place indorder for the routine to be carried out
	Call Int;
	Call Enable;
	Call IntTime;
	Call Int;
	Call Enable;
	Call IntTime;
	Call FunSet; Calls the function set code
	Call Enable;
	Call IntTime;
	Call Disoff; Calls the display off code
	Call Enable;
	Call IntTime;
	Call Dison; Calls the display on code
	Call Enable;
	Call IntTime;
	Call Disclr; Calls the display clear code
	Call Enable;
	Call IntTime;
	Call Ent; calls the entry mode code
	Call Enable;
	Call IntTime;
        Call DDRAM1; calls the DDRAM1 code to give the position of the display
        Call Enable;
        Call IntTime;
        Call A; calls the ASCII code to display the letter A
        Call Enable;
        Call IntTime;
Stop:   goto Stop;


Setup: movlw 0x00; moves the value 0 to the w reg to set port up as output
       tris 0x05; sets port a as output
       movlw 0x00;
       tris 0x06; sets port b as output
       movlw 0xff; moves the value ff to w reg to set port as input
       tris 0x07; sets port c as input
       movlw 0x04; sends the value 04 to the w reg
       option; sets up timmer
       return; returns the program to main routine

Int: bcf 0x05,0; Clears bit 0 port a
     bcf 0x05,1; clears bit 1 port a
     bcf 0x05,2; clears bit 2 port a
     movlw 0x30; moves 30 to w reg
     movwf 0x06; moves the value 30 to port b
     return;

Enable: bsf 0x05,2; sets bit 2 at port a to a logic 1
        bcf 0x05,2; sets bit 2 port a to a logic 0
        return;

IntTime: movlw 0x05; moves the value 5 to w reg
         movwf 0x0a; moves 5 to file 0a
again:   clrf 0x01; clears timer
loop:    movlw 0x7d; moves the value 7d to w reg
         subwf 0x01,0; subtract 1 away from the value 7d
         btfss 0x03,2; bit test the status reg and skips if set
         goto loop; goes to loop
         decfsz 0x0a,1; takes one away from file 0a and skips next instruction if its 0
         goto again; goes to again
         
         return;

FunSet: bcf 0x05,0; Sets the RS to 0
        bcf 0x05,1;  Sets the R/W to 0
        movlw 0x34; moves the hexadecimal value 34 (00110100) makes it 8 bits,1 line and 5x10 dot characters used
        movwf 0x06; sends the value 34 to port b
        return;

Disoff: bcf 0x05,0;
        bcf 0x05,1;
        movlw 0x08;moves the hexadecimal value 08 (00001000) makes display off, cursor off and blinking off
        movwf 0x06;moves the value 08 to port b
        return;

Dison: bcf 0x05,0;
       bcf 0x05,1;
       movlw 0x0e; moves the hexadecimal value 0e (00001110) makes the diaplay on, cursor on and blinking off
       movwf 0x06;
       return;

Disclr: bcf 0x05,0;
        bcf 0x05,1;
        movlw 0x01; move the hexadecimal value 01(00000001) calls for the display to be cleared
        movwf 0x06;
        return;

Ent: bcf 0x05,0;
     bcf 0x05,1;
     movlw 0x06; moves the hexadecimal value 06 (00000110) makes crusor position increment(left to right) and display remains still while cursor moves
     movwf 0x06;
     return;

DDRAM1: bcf 0x05,0;
        bcf 0x05,1;
        movlw 0x07; moves thr hexadecimal value 07 making the display postion in the middle
        movwf 0x06;
        return;

A:      bsf 0x05,0; Sets the RS to 1 to select the data register and send information to the LCD
        bcf 0x05,1;
        movlw 0x41; moves the hexadecimal value 41 (01000001) ASCII value for the letter A
        movwf 0x06;
        return; 
	org 0x1FF;
	goto 0x00;

	end;