;Experiment-11 for "5x7 Video Screen" Project      
  	        ;PIC16F84 and only F84 chip         
      		    ;  ELEVATOR DISPLAY
	
Start   ORG 0x00
        BSF 03,5        ;Go to page1 for setting-up the ports	 
	MOVLW 0Ch       ;Put 0C into W     
	MOVWF 05h       ;  to make RA2 & RA3 input 
	MOVLW 00h	;Put 00 into W   
        MOVWF 06h       ;to make all RB lines output
        BCF 03,5        ;Go to Page0 for programming
	GOTO Main




Table1	ADDWF 02h,1	;Add W to Program Counter
	RETLW 0Eh
	RETLW 11h
	RETLW 11h
	RETLW 0Fh
	RETLW 01h
	RETLW 11h
	RETLW 0Eh
	RETLW 00h
	RETLW 0Eh
	RETLW 11h
	RETLW 11h
	RETLW 0Eh
	RETLW 11h
	RETLW 11h
	RETLW 0Eh	
	RETLW 00h
	RETLW 1Fh
	RETLW 02h
	RETLW 02h
	RETLW 04h
	RETLW 08h
	RETLW 08h
	RETLW 08h
	RETLW 00h
	RETLW 0Eh
	RETLW 11h
	RETLW 10h
	RETLW 1Eh
	RETLW 11h
	RETLW 11h
	RETLW 0Eh
	RETLW 00h
	RETLW 1Fh
	RETLW 10h
	RETLW 10h
	RETLW 1Eh
	RETLW 01h
	RETLW 11h
	RETLW 0Eh
	RETLW 00h
	RETLW 02h
	RETLW 06h
	RETLW 0Ah
	RETLW 12h
	RETLW 1Fh
	RETLW 02h
	RETLW 02h
	RETLW 00h
	RETLW 0Eh
	RETLW 11h
	RETLW 01h
	RETLW 06h
	RETLW 01h
	RETLW 11h
	RETLW 0Eh
	RETLW 00h
	RETLW 0Eh
	RETLW 11h
	RETLW 01h
	RETLW 0Eh
	RETLW 10h
	RETLW 10h
	RETLW 1Fh
	RETLW 00h
	RETLW 04h
	RETLW 0Ch
	RETLW 14h
	RETLW 04h
	RETLW 04h
	RETLW 04h
	RETLW 04h
	RETLW 00h
	RETLW 0Eh
	RETLW 11h
	RETLW 10h
	RETLW 17h
	RETLW 11h
	RETLW 11h
	RETLW 0Eh
	RETLW 00h
	RETLW 00h
	


    ;Ghost routine transfers data from the 
    ;        Ghost files to the Video Screen
	;  and scans the Video Screen ONCE

Ghost	BSF 05,1	;Reset 4017
	NOP
	BCF 05,1

	MOVF 11h,0
	MOVWF 06h
	CALL DelA
	MOVF 12h,0
	MOVWF 06h
	CALL DelA
	MOVF 13h,0
	MOVWF 06h
	CALL DelA
	MOVF 14h,0
	MOVWF 06h
	CALL DelA
	MOVF 15h,0
	MOVWF 06h
	CALL DelA
	RETURN

DelA	DECFSZ 1Bh,1
	GOTO DelA
	MOVLW 00h
	MOVWF 06
Clk	BCF 05,0
	NOP
	BSF 05,0
	RETURN
	


     ;FillTop moves the 5 Ghost locations down one bit
	; and fills the top row with new data.
	;File 16h contains the new data for the 5 locations

FillTop	RRF 11h,1
	RRF 12h,1
	RRF 13h,1
	RRF 14h,1
	RRf 15h,1
	BCF 11h,6
	BCF 12h,6
	BCF 13h,6
	BCF 14h,6
	BCF 15h,6
	BTFSS 16h,4
	GOTO L
	BSF 11h,6
L	BTFSS 16h,3
	GOTO M
	BSF 12h,6
M	BTFSS 16h,2
	GOTO N
	BSF 13h,6
N	BTFSS 16h,1
	GOTO O
	BSF 14h,6
O	BTFSS 16h,0
	RETURN
	BSF 15h,6
	RETURN



          ;FilGho fills the Ghost area with 7 rows of "G" data
		;from Table1

	
FilGho	MOVLW 07
	MOVWF 1A	;1A is count file for 7 cycles of "FilGho"
	MOVLW 4Eh	;Jump down table1 xxh locations
	MOVWF 17h	;file17h is pointer for Table1
FilGho1	CALL Table1
	MOVWF 16h
	CALL FillTop
	DECF 17h,1
	MOVF 17h,0	;Put pointer into W
	DECFSZ 1A,1
	GOTO FilGho1
	RETURN 
	

	
	;

Main	CALL FilGho	;Put "G" on screen
	CALL Ghost	;Display whatever is in Ghost files
	BTFSS 05h,2	;Test for buttonA
	GOTO Main2		;Pushed
	GOTO Main  



Main2	MOVLW 08
	MOVWF 1A
Main3	MOVLW 20h
	MOVWF 18h	;18h = number of scans before adding next row
Main4	CALL Ghost
	DECFSZ 18h,1
	GOTO Main4
	MOVF 17h,0	;Put table1 pointer into W
	CALL Table1
	MOVWF 16h
	CALL FillTop
	DECF 17h,1
	DECFSZ 1A,1
	GOTO Main3	
Main5	CALL Ghost	;Display whatever is in Ghost files
	BTFSS 05h,2	;Test for buttonA
	GOTO Main2		;Pushed
	GOTO Main5

        END