title  "LcdTerminal 16F873 or 16F628"

;  
;
;  Hardware Notes:
; 20 MHz osc 115200 baud
;
;  Ted Rossin:  04-13-2003
;	            06-05-2003

; ************************************************
; **									        **
; ** Special characters:                        **
; **   0x01  Home                               **
; **   0x08  Back space                         **
; **   0x09  Tab                                **
; **   0x0a  Line feed ^J                       **
; **   0x0c  Form feed (Clear display)          **
; **   0x0d  Carriage return ^M                 **
; **   0x10  Move to X,Y (X and Y are the       **
; **         next two characters                **
; **   0x1b  Escape                             **
; **           0x00 Disable cursor              **
; **           0x01 Enable underscore cursor    **
; **           0x02 Enable block cursor         **
; **           0x03 Scroll display left         **
; **           0x04 Scroll display right        **
; **           0x05 Enable Display              **
; **           0x06 Disable Display             **
; **           0x07 Raw LCD controller command  **
; **           0x08 Disable vertical scroll     **
; **           0x09 Enable vertical scroll(default)**           
; **           0x10 Write Custom character 0    **
; **                Next 8 bytes form character **
; **           0x11 Write Custom character 1    **
; **                Next 8 bytes form character **
; **           0x12 Write Custom character 2    **
; **                Next 8 bytes form character **
; **           0x13 Write Custom character 3    **
; **                Next 8 bytes form character **
; **           0x14 Write Custom character 4    **
; **                Next 8 bytes form character ** 
; **           0x15 Write Custom character 5    **
; **                Next 8 bytes form character ** 
; **           0x16 Write Custom character 6    **
; **                Next 8 bytes form character ** 
; **           0x17 Write Custom character 7    **
; **                Next 8 bytes form character **  
; **   0x80 Display custom character 0          **
; **   0x81 Display custom character 1          **
; **   0x82 Display custom character 2          **
; **   0x83 Display custom character 3          **
; **   0x84 Display custom character 4          **
; **   0x85 Display custom character 5          **
; **   0x86 Display custom character 6          **
; **   0x87 Display custom character 7          **
; **                                            **
; ************************************************

	LIST R=DEC

	; Used for development
	
#ifdef __16F873

#include "p16f873.inc"

#define LCD_RS		PORTC,2
#define LCD_E		PORTC,3
#define BAUD_SELECT PORTC,4 

    __CONFIG _CP_OFF & _DEBUG_OFF & _HS_OSC & _PWRTE_ON  & _WDT_OFF & _LVP_OFF & _WRT_ENABLE_ON & _BODEN_ON & _CPD_OFF

#endif

	; Used for product
	
#ifdef __16F628

#include "P16f628.inc"

#define LCD_RS		PORTA,2
#define LCD_E		PORTA,3
#define BAUD_SELECT PORTA,5  

#define _CPD_OFF	0x3fff  ; Missing define
#define _CPD_ON		0x3eff  ; Missing define
 	__CONFIG _HS_OSC & _CP_OFF & _CPD_OFF & _LVP_OFF & _BODEN_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF

#endif


#define PRESCALE_TIMER_MODE	0xD0
#define PRESCALE_VALUE	(PRESCALE_TIMER_MODE | 0x8)	; Set prescaler to 1/1

#define TERM_HOME   0x01    ; SOH
#define TERM_BS     0x08    ; BS
#define TERM_TAB    0x09    ; HTAB
#define TERM_LF     0x0a    ; LF (Line feed) ^J
#define TERM_CLEAR  0x0c    ; FF
#define TERM_CR     0x0d    ; CR (Carriage return) ^M
#define TERM_POS    0x10    ; Move to X,Y
#define TERM_ESC    0x1b    ; More fun ahead

#define ESC_DISABLE_CURSOR      0x00
#define ESC_ENABLE_UNDER_CURSOR 0x01
#define ESC_ENABLE_BLOCK_CURSOR 0x02
#define ESC_SCROLL_LEFT         0x03
#define ESC_SCROLL_RIGHT        0x04
#define ESC_ENABLE_DISPLAY      0x05
#define ESC_DISABLE_DISPLAY     0x06
#define ESC_RAW_COMMAND         0x07
#define ESC_DISABLE_VERT_SCROLL 0x08
#define ESC_ENABLE_VERT_SCROLL  0x09
#define ESC_WRITE_CUSTOM        0x10
#define DISPLAY_CUSTOM_MASK     0xf8
#define DISPLAY_CUSTOM_VALUE    0x80

#define STATE_NORMAL        0
#define STATE_WAIT_X        1
#define STATE_WAIT_Y        2
#define STATE_WAIT_COMMAND  3

#define FLAGS_DISABLE_VERT_SCROLL    0


	;  RAM

#define FIFO_START  0xA0
#define FIFO_END    0xEF

#define REG_START	0x020

	cblock	REG_START
	    _w, _status, _fsr   ;  Context Register Save Values
	    Amount			 
	    DelayL,DelayH
	    LcdX,LcdY
	    Tmp,Tmp2
        Loop1
        Count
        State
        Flags
        LastRS232Byte
        CgRamAddr
	    Param:2			    ; Parameters
                            ; Input FIFO
        Empty
        FifoWritePtr
        FifoReadPtr
                            ; Scroll buffer
        ScrollBuffer1:20
        ScrollBuffer2:20
        ScrollBuffer3:20
 	endc

 	
	org     0

Startup:
	nop
	nop
	nop
	goto   Main


; ************************************************
; **									        **
; ** Interrupt handler	                        **
; **									        **
; ************************************************
      
	org     4
  
Int:
  	movwf	_w		    ; Save Context Registers
  	movf	STATUS, w	; - Assume TMR0 is the only enabled Interrupt
  	movwf	_status
	movf	FSR,w
	movwf	_fsr
	
    bcf	    PIR1,RCIF	    ; Clear the recieved data flag
                            ; Write byte to FIFO to full check
    movf    FifoWritePtr,w
    movwf   FSR
    movf	RCREG,w
    movwf   INDF
    bcf     Empty,0         ; Clear the empty flag
    incf    FifoWritePtr,f
    movf    FifoWritePtr,w
    sublw   FIFO_END
    btfss	STATUS,Z		; Skip if need to wrap write pointer
	  goto IntEnd
    movlw   FIFO_START
    movwf   FifoWritePtr

IntEnd:
	movf	_fsr,w		; Restore registers
	movwf	FSR
  	movf   _status, w	
  	movwf  STATUS
  	swapf  _w, f
  	swapf  _w, w
    retfie


; ************************************************************************
; **									                                **
; ** GetRS232Byte: Waits for a byte to be received and then returns it	**
; **               in w.						                        **
; **									                                **
; ************************************************************************

GetRS232Byte:
	btfsc	Empty,0	        ; Wait for byte to show up.
	  goto	$-1
    movf    FifoReadPtr,w   ; Fetch byte from FIFO
    movwf   FSR
    movf    INDF,w
    movwf   Tmp

    incf    FifoReadPtr,f
    movf    FifoReadPtr,w
    sublw   FIFO_END
    btfss	STATUS,Z		; Skip if need to wrap write pointer
	  goto GetRS232ByteEnd
    movlw   FIFO_START
    movwf   FifoReadPtr
GetRS232ByteEnd
    
    movf    FifoReadPtr,w
    subwf   FifoWritePtr,w
    btfss   STATUS,Z
      goto  GetRS232ByteSkip
    bsf     Empty,0         ; Set the empty flag
GetRS232ByteSkip
    movf    Tmp,w
	return

; ************************************************************************
; **									                                **
; ** SendRS232Byte: Waits for transmit to be ready and then sends byte	**
; **                in w to the RS-232 port				                **
; **									                                **
; ************************************************************************

SendRS232Byte:
	btfss	PIR1,TXIF
	  goto	$-1
	movwf	TXREG
	return;

; ************************************************************************
; **									                                **
; ** InitRS232:								                            **
; **	Initialize the RS-232 port for recieve interrupt operation.     **
; **									                                **
; ************************************************************************

InitRS232:
	bcf	STATUS,RP0
	bcf	STATUS,RP1		    ; Select Bank 0	
	bsf	STATUS,RP0          ; Select Bank 1 registers
#ifdef __16F873 
	bsf	TRISC^0x80,7        ; PORTC[RX] is Input
	bcf	TRISC^0x80,6        ; PORTC[TX] is Output
#else
    bsf TRISB^0x80,1        ; PORTB[RX] is Input
    bcf TRISB^0x80,2        ; PORTB{TX] is Output
#endif

    bcf	STATUS,RP0		    ; Select Bank 0
    movlw   129             ; Set baud to 9600
    btfss   BAUD_SELECT     ; Check to see if High baud rate
	 movlw	10              ; Set baud to 115200

    bsf	STATUS,RP0          ; Select Bank 1 registers
;   movlw   20              ; Set baud to 57600   
	movwf	SPBRG^0x80		; 
	movlw	(1<<TXEN)|(1<<BRGH)
	movwf	TXSTA^0x80		; Set transmit mode
    movlw	(1<<RCIE)
	iorwf	PIE1^0x80,f		; Enable receive interrupts
	bcf	STATUS,RP0		    ; Select Bank 0
	movlw	(1<<SPEN)|(1<<CREN)
	movwf	RCSTA			; Set receive mode 
    bsf     Empty,0         ; Set the empty flag

    movlw   FIFO_START
    movwf   FifoWritePtr
    movwf   FifoReadPtr
	return

    ;
    ; InitWaitTimer
    ;

InitWaitTimer:
	bcf	STATUS,RP0
	bcf	STATUS,RP1
	movlw	0x01		; timer 1 internal 1:1 prescale
	movwf	T1CON
	clrf	TMR1L
	clrf	TMR1H
	return

    ;
    ; Waitms
    ;

Waitms:
WaitmsLoop:
	bcf	T1CON,0	; Disable Timer
	movlw	255-19
	movwf	TMR1H
	movlw	255-(136-12)
	movwf	TMR1L
	bsf	T1CON,0	; Enable Timer
WaitmsInnerLoop:
	btfsc	TMR1H,7
	  goto	WaitmsInnerLoop
	decfsz	Amount,f
	  goto	WaitmsLoop
	return;

    ;
    ; Waitus
    ;

Waitus:
	bcf	T1CON,0	; Turn off timer
	movlw	5
	subwf	Amount,w
	movwf	DelayL
	bcf	STATUS,C
	clrf	DelayH
	rlf	DelayL,f
	rlf	DelayH,f
	rlf	DelayL,f
	rlf	DelayH,f
	movlw	5
	subwf	Amount,w
	addwf	DelayL,f
	btfsc	STATUS,C
	  incf	DelayH,f
			; {DelayH,DelayL} = Amount*5
	movf	DelayL,w
	sublw	255	; 255-DelayL
	movwf	TMR1L
	movf	DelayH,w
	sublw	255
	movwf	TMR1H
	bsf	T1CON,0	; Turn on Timer

	movlw	5-1
	subwf	Amount,w
	btfss	STATUS,C
	  return;	; return if Amount < 5us
WaitusLoop:
	btfsc	TMR1H,7
	  goto	WaitusLoop
	return

    ;
    
    
WriteData:

#ifdef __16F873
    movwf   PORTB
#else
        ; Swizzle byte data between PORT A and B
        ; {PB7,PB6,PB5,PB4,PB3,PB0,PA1,PA0} = w[7:0]
    movwf   Tmp
    andlw   0xfc
    movwf   PORTB
    btfsc   Tmp,2
      bsf   PORTB,0

    movf    Tmp,w
    andlw   0x03
    movwf   Param
    movf    PORTA,w
    andlw   0xfc
    iorwf   Param,w
    movwf   PORTA
#endif
    return

    ;
    ; Writes the character in W to LCD display
    ;
LcdPutChar:
    movwf   Tmp
    call    WriteData

	bsf	    LCD_RS	
	bsf	    LCD_E
    nop
	bcf	    LCD_E
                    ; Save data in Scroll Buffer

    movf   LcdY,w
    addlw	0-0	; Check for 0
	btfsc	STATUS,Z
	  goto	LcdPutCharFinish

	movf   LcdY,w
    addlw	256-1	; Check for 1
	btfsc	STATUS,Z
	  goto	LcdPutCharLine1

    movf   LcdY,w
    addlw	256-2	; Check for 2
	btfsc	STATUS,Z
	  goto	LcdPutCharLine2

    goto    LcdPutCharLine3


LcdPutCharLine1:
    movlw	ScrollBuffer1
    goto    LcdPutCharSave

LcdPutCharLine2:
    movlw	ScrollBuffer2
    goto    LcdPutCharSave

LcdPutCharLine3
    movlw   ScrollBuffer3
    
LcdPutCharSave:    
	movwf	FSR
    movf    LcdX,w
    addwf   FSR,f
    movf    Tmp,w
    movwf   INDF    ; Write data into buffer

LcdPutCharFinish:
    incf	LcdX,f
	movlw	40
	movwf	Amount
	call	Waitus
	return

    ;
    ; LcdWriteCommand: Writes the command in w to the LCD disply
    ;

LcdWriteCommand:
    movwf   Tmp
    call    WriteData

	bcf	    LCD_RS
	bsf	    LCD_E
	nop
	bcf	    LCD_E
	movlw	40
	movwf	Amount
	call	Waitus
	return

    ;
    ; LcdClearDisplay: Clears LCD display
    ;

LcdClearDisplay:
	movlw	0x01			; Clear display
    call    WriteData

    bcf	    LCD_RS
	bsf	    LCD_E
	nop
	bcf	    LCD_E
	clrf	LcdX
	clrf	LcdY
	movlw	2
	movwf	Amount
	call	Waitms
	return

    ;
    ; InitLcd:  Initializes LCD display
    ;

LcdInit:
	bcf	    LCD_RS			; Turn off stobes to LCD display
	bcf	    LCD_E

                        ; Clear scroll buffers
    clrf    Count
    movlw	20
	movwf	Loop1
LcdInitLoop:
    movlw   ScrollBuffer1
	movwf	FSR
    movf    Count,w
    addwf   FSR,f
    movlw   ' '         ; Replace with blank
    movwf   INDF

    movlw   ScrollBuffer2
	movwf	FSR
    movf    Count,w
    addwf   FSR,f
    movlw   ' '         ; Replace with blank
    movwf   INDF

    movlw   ScrollBuffer3
	movwf	FSR
    movf    Count,w
    addwf   FSR,f
    movlw   ' '         ; Replace with blank
    movwf   INDF

	incf	Count,f
	decfsz	Loop1,f
	    goto LcdInitLoop

	movlw	100
	movwf	Amount
	call	Waitms			; Wait for LCD to power up
	
	call	LcdClearDisplay

	movlw	0x38			; Set Function
	call	LcdWriteCommand	
	movlw	0x0c			; Turn on display (no cursor)
	call	LcdWriteCommand
	movlw	0x06			; Set Entry Mode
	call	LcdWriteCommand
	return

    ;
    ; LcdSetPos 
    ;

LcdSetPos:

	movlw	0x80	; Lcd Set Addr Command
	addwf	LcdX,w	; Add X offset
	btfsc	LcdY,0
	  addlw	0x40	; Odd line Y offset
	btfsc	LcdY,1
	  addlw	0x14	; Lines 2 and 3 offset

    movwf   Tmp
    call    WriteData

	bcf	    LCD_RS
	bsf	    LCD_E
	nop
	bcf	    LCD_E
	movlw	40
	movwf	Amount
	call	Waitus
	return

#ifdef FLASH_MEMORY_ACCESS
    ;
    ; LcdDisplayString(Param+1,Param+0)  {Param+1,param+0} form 16-bit address pointer
    ; The string must be located in flash memory code space
    ;
	
LcdDisplayString:
	movf	Param+1,w	; Fetch low address (assume bank 0)
	bsf	STATUS,RP1
	bcf	STATUS,RP0	; Bank2	
	movwf	EEADR^0x100	; Set low address
	bcf	STATUS,RP1	; Bank 0
	movf	Param+0,w
	bsf	STATUS,RP1	; Bank 2
	movwf	EEADRH^0x100	; Set high address
LcdDisplayStringLoop:
	bsf	STATUS,RP0	; Bank3
	bsf	EECON1^0x180,EEPGD	; Point to Program memory	
	bsf	EECON1^0x180,RD	; Start read operation
	nop			; two required NOPs
	nop
	bcf	STATUS,RP0	; Bank2
	movf	EEDATA^0x100,w	; Fetch Low Byte
	bcf	STATUS,RP1	; Bank0
	addlw	0		; Check for end of string
	btfsc	STATUS,Z
	  return		; End of string			
	addlw	256-'\n'	; Check for \n
	btfsc	STATUS,Z
	  goto	LcdDisplayStringNewLine
	addlw	'\n'		; Restore check value
	call	LcdPutChar
LcdDisplayStringAdvance:
	bsf	STATUS,RP1	; Bank 2
	incf	EEADR^0x100,f	; Advance read pointer
	btfsc	STATUS,Z	
	  incf	EEADRH^0x100,f	; Advance high order address if overflow
	goto	LcdDisplayStringLoop
LcdDisplayStringNewLine:
	clrf	LcdX
	incf	LcdY,f
	call	LcdSetPos	; Goto (LcdX,LcdY)
	goto	LcdDisplayStringAdvance

#endif

    ;
    ;  Main Program
    ;

Main:
	bcf		STATUS,RP0
	bcf		STATUS,RP1

	call 	InitWaitTimer



	bcf		STATUS,RP1
	bsf		STATUS,RP0		; Select Bank 1

#ifdef __16F873

	movlw	0x2f			; Port A[3:0],A[5] are input for A/D				
	movwf	TRISA^0x80

	clrf	TRISB^0x80      ; PORTB is Output
	movlw	0x10			; Output PORTC[7:5],PORTC[3:0], Input PORTC[4]
	movwf	TRISC^0x80          	          	

	movlw	0x00			; (left justified data) 8 or 5 A/D channels
	movwf	ADCON1^0x80
	bcf	    STATUS,RP0      ; Go back to Bank 0
	movlw	0x81			; FOSC/32, channel=0, ADON=1
	movwf	ADCON0
#else

	bcf		STATUS,RP0		; Select Bank 0
	
   	movlw	0x07
	movwf	CMCON			; Turn off 16F82x comparators to save power

	bsf		STATUS,RP0		; Select Bank 1

    movlw	0x20			; Port A[4] is input, Port A[3:0] are output
    movwf   TRISA^0x80      ; PORTA is Output
    clrf	TRISB^0x80      ; PORTB is Output

#endif

	bsf	    STATUS,RP0          ; Go to Bank 1
	movlw  	PRESCALE_VALUE		; Set Timer 0 prescale value 
	movwf	OPTION_REG^0x080
	
	bcf		STATUS,RP0            	; Go back to Bank 0

	call	LcdInit
	call	LcdClearDisplay
	call	InitRS232
								; Initialize varibles
	clrf	LcdX
	clrf	LcdY
    clrf    LastRS232Byte
    clrf    Flags

    movlw   STATE_NORMAL
    movwf   State

    movlw  	(1<<GIE) | (1<<PEIE)
	movwf  	INTCON		; Enable Interrupts	

TheLoop:
    movf    State,w
	addlw	STATE_NORMAL	; Check
	btfsc	STATUS,Z
	  goto	NormalState
	addlw	STATE_NORMAL		; Restore check value

	addlw	256-STATE_WAIT_X	; Check
	btfsc	STATUS,Z
	  goto	WaitXState
	addlw	STATE_WAIT_X		; Restore check value

	addlw	256-STATE_WAIT_Y	; Check
	btfsc	STATUS,Z
	  goto	WaitYState
	addlw	STATE_WAIT_Y		; Restore check value

	addlw	256-STATE_WAIT_COMMAND	; Check
	btfsc	STATUS,Z
	  goto	EscCommand
	addlw	STATE_WAIT_COMMAND		; Restore check value
    
    goto    TheLoop

WaitXState:
    call	GetRS232Byte
    movwf   LcdX
    movlw   STATE_WAIT_Y
    movwf   State
    goto    TheLoop

WaitYState:
    call	GetRS232Byte
    movwf   LcdY
    movlw   STATE_NORMAL
    movwf   State
    call    LcdSetPos	; Goto (LcdX,LcdY)
    goto    TheLoop

        ;
        ; Process Esc command
        ;

EscCommand:
    movlw   STATE_NORMAL
    movwf   State
    call	GetRS232Byte

	addlw	ESC_DISABLE_CURSOR	; Check
	btfsc	STATUS,Z
	  goto	DisableCursor
	addlw	ESC_DISABLE_CURSOR		; Restore check value

	addlw	256-ESC_ENABLE_UNDER_CURSOR	; Check
	btfsc	STATUS,Z
	  goto	EnableUnderCursor
	addlw	ESC_ENABLE_UNDER_CURSOR		; Restore check value

	addlw	256-ESC_ENABLE_BLOCK_CURSOR	; Check
	btfsc	STATUS,Z
	  goto	EnableBlockCursor
	addlw	ESC_ENABLE_BLOCK_CURSOR		; Restore check value

	addlw	256-ESC_SCROLL_LEFT	; Check
	btfsc	STATUS,Z
	  goto	ScrollLeft
	addlw	ESC_SCROLL_LEFT		; Restore check value

	addlw	256-ESC_SCROLL_RIGHT	; Check
	btfsc	STATUS,Z
	  goto	ScrollRight
	addlw	ESC_SCROLL_RIGHT		; Restore check value

	addlw	256-ESC_ENABLE_DISPLAY	; Check
	btfsc	STATUS,Z
	  goto	EnableDisplay
	addlw	ESC_ENABLE_DISPLAY		; Restore check value

	addlw	256-ESC_DISABLE_DISPLAY	; Check
	btfsc	STATUS,Z
	  goto	DisableDisplay
	addlw	ESC_DISABLE_DISPLAY		; Restore check value

	addlw	256-ESC_RAW_COMMAND	; Check
	btfsc	STATUS,Z
	  goto	RawCommand
	addlw	ESC_RAW_COMMAND		; Restore check value

	addlw	256-ESC_DISABLE_VERT_SCROLL	; Check
	btfsc	STATUS,Z
	  goto	DisableVertScroll
	addlw	ESC_DISABLE_VERT_SCROLL		; Restore check value

	addlw	256-ESC_ENABLE_VERT_SCROLL	; Check
	btfsc	STATUS,Z
	  goto	EnableVertScroll
	addlw	ESC_ENABLE_VERT_SCROLL		; Restore check value


    movwf   LastRS232Byte
    andlw   DISPLAY_CUSTOM_MASK   
	addlw	256-ESC_WRITE_CUSTOM	; Check
	btfsc	STATUS,Z
	  goto	WriteCustomChar
	movf    LastRS232Byte,w
    
    goto    TheLoop

DisableCursor:
    movlw   0x0c
    call    LcdWriteCommand
    goto    TheLoop

EnableUnderCursor:
    movlw   0x0e
    call    LcdWriteCommand
    goto    TheLoop

EnableBlockCursor:
    movlw   0x0f
    call    LcdWriteCommand
    goto    TheLoop

ScrollLeft:
    movlw   0x18
    call    LcdWriteCommand
    goto    TheLoop

ScrollRight:
    movlw   0x1c
    call    LcdWriteCommand
    goto    TheLoop

EnableDisplay:
    movlw   0x0c
    call    LcdWriteCommand
    goto    TheLoop

DisableDisplay:
    movlw   0x08
    call    LcdWriteCommand
    goto    TheLoop

RawCommand:
    movf    LastRS232Byte,w
    call    LcdWriteCommand
    goto    TheLoop

DisableVertScroll:
    bsf     Flags,FLAGS_DISABLE_VERT_SCROLL
    goto    TheLoop

EnableVertScroll:
    bcf     Flags,FLAGS_DISABLE_VERT_SCROLL
    goto    TheLoop

WriteCustomChar:
    movf    LastRS232Byte,w
    andlw   0x7             ; Just get character ID
    movwf   CgRamAddr
    bcf     STATUS,C
    rlf     CgRamAddr,f
    rlf     CgRamAddr,f
    rlf     CgRamAddr,f       ; Set character Ram address
    movlw   8
    movwf   Count
WriteCustomCharLoop:
    movf    CgRamAddr,w
    iorlw   0x40
    call    LcdWriteCommand
    call	GetRS232Byte
    call    LcdPutChar      ; Write the data
    decf    LcdX,f          ; undo inc of LcdX
    incf    CgRamAddr,f
	decfsz	Count,f
      goto  WriteCustomCharLoop
                        ; Go back to normal character mode
    call	LcdSetPos	; Goto (LcdX,LcdY)
    goto    TheLoop
    
    ;
    ; Normal single character
    ;

NormalState:
	call	GetRS232Byte

      ; Lame case statement 
	addlw	256-TERM_LF	; Check for \n
	btfsc	STATUS,Z
	  goto	PreTerminalNewLine1
	addlw	TERM_LF		; Restore check value

	addlw	256-TERM_CR	; Check for \r
	btfsc	STATUS,Z
	  goto	PreTerminalNewLine2
	addlw	TERM_CR		; Restore check value

    movwf   LastRS232Byte

    addlw	256-TERM_BS	; Check for BS
	btfsc	STATUS,Z
	  goto	TerminalBackSpace
	addlw	TERM_BS		; Restore check value

    addlw	256-TERM_HOME ; Check
	btfsc	STATUS,Z
	  goto	TerminalHome
	addlw	TERM_HOME		; Restore check value

    addlw	256-TERM_CLEAR ; Check
	btfsc	STATUS,Z
	  goto	TerminalClear
	addlw	TERM_CLEAR	; Restore check value

    addlw	256-TERM_TAB ; Check
	btfsc	STATUS,Z
	  goto	TerminalTab
	addlw	TERM_TAB	; Restore check value

    addlw	256-TERM_POS ; Check
	btfsc	STATUS,Z
	  goto	TerminalPos
	addlw	TERM_POS	; Restore check value

    addlw	256-TERM_ESC ; Check
	btfsc	STATUS,Z
	  goto	TerminalEscape
	addlw	TERM_ESC	; Restore check value
    
    movf    LcdX,w
    addlw   256-20
    btfsc   STATUS,Z
      call  TerminalNewLine

    movf    LastRS232Byte,w
    andlw   DISPLAY_CUSTOM_MASK
    addlw	256-DISPLAY_CUSTOM_VALUE ; Check
	btfsc	STATUS,Z
	  goto  DisplayCustomChar

    movf    LastRS232Byte,w
	call	LcdPutChar
      
	goto	TheLoop

PreTerminalNewLine1:    ; \n received
    movf    LastRS232Byte,w
	addlw	256-TERM_CR	; Check for previous \r
	btfsc	STATUS,Z
	  goto	TheLoop
    movlw   TERM_LF
    movwf   LastRS232Byte
PreTerminalNewLine:  
    call    TerminalNewLine
    goto    TheLoop

PreTerminalNewLine2:    ; \r received
    movf    LastRS232Byte,w
	addlw	256-TERM_LF	; Check for previous \n
	btfsc	STATUS,Z
	  goto	TheLoop
    movlw   TERM_CR
    movwf   LastRS232Byte    
    call    TerminalNewLine
    goto    TheLoop

TerminalNewLine:
    clrf	LcdX
	incf	LcdY,f
	movf	LcdY,w
    addlw	256-4	; Check for need to scroll
	btfsc	STATUS,Z
	  call	ScrollDisplay
    call	LcdSetPos	; Goto (LcdX,LcdY)
    return

TerminalBackSpace:
    movf    LcdX,w
    addlw   0           ;Check for zero
    btfsc STATUS,Z
      goto  TheLoop
	decf	LcdX,f
	call	LcdSetPos	; Goto (LcdX,LcdY)
    movlw   ' '
    call    LcdPutChar  ; Remove character
    decf    LcdX,f
    call	LcdSetPos	; Goto (LcdX,LcdY)
	goto	TheLoop

TerminalHome:
    clrf	LcdX
	clrf	LcdY
    call	LcdSetPos	; Goto (LcdX,LcdY)
    goto	TheLoop

TerminalClear:
    call    LcdClearDisplay
    goto	TheLoop

TerminalTab:
    movf    LcdX,w
    addlw   4
    andlw   0xfc    ; Snap to tab stop
    movwf   LcdX    ; Save new value
    addlw   256-20
    btfsc   STATUS,Z
      goto  PreTerminalNewLine
    call    LcdSetPos
    goto    TheLoop

TerminalPos:
    movlw   STATE_WAIT_X
    movwf   State
    goto    TheLoop

TerminalEscape:
    movlw   STATE_WAIT_COMMAND
    movwf   State
    goto    TheLoop

DisplayCustomChar:    
    movlw   DISPLAY_CUSTOM_VALUE
    subwf   LastRS232Byte,w     ; w = LastRS232Byte - DISPLAY_CUSTOM_MASK
    call	LcdPutChar
    goto    TheLoop

    ;*************************************************
    ;**                                             **
    ;**  ScrollDisplay:                             **
    ;**                                             **
    ;*************************************************

ScrollDisplay:
    btfsc   Flags,FLAGS_DISABLE_VERT_SCROLL
      goto  DoNotScrollDisplay    
    call	LcdClearDisplay

    clrf    Count
	movlw	20
	movwf	Loop1
ScrollDisplayLoop1:
    movlw    ScrollBuffer1  
	movwf	FSR
    movf    Count,w
    addwf   FSR,f
    movf    INDF,w 
    call    LcdPutChar

	incf	Count,f
	decfsz	Loop1,f
	    goto ScrollDisplayLoop1

    clrf    LcdX
    incf    LcdY,f
	call	LcdSetPos	; Goto (LcdX,LcdY)
    clrf    Count
	movlw	20
	movwf	Loop1
ScrollDisplayLoop2:
    movlw    ScrollBuffer2  
	movwf	FSR
    movf    Count,w
    addwf   FSR,f
    movf    INDF,w 
    call    LcdPutChar

	incf	Count,f
	decfsz	Loop1,f
	    goto ScrollDisplayLoop2

        ; Copy line 3 to line 2 and clear line 3 buffer

    clrf    LcdX
    incf    LcdY,f
	call	LcdSetPos	; Goto (LcdX,LcdY)
    clrf    Count
	movlw	20
	movwf	Loop1
ScrollDisplayLoop3:
    movlw    ScrollBuffer3
	movwf	FSR
    movf    Count,w
    addwf   FSR,f
    movf    INDF,w
    movwf   Tmp
    movlw   ' '         ; Replace with blank
    movwf    INDF
    movf    Tmp,w
    call    LcdPutChar

	incf	Count,f
	decfsz	Loop1,f
	    goto ScrollDisplayLoop3

DoNotScrollDisplay:
    clrf	LcdX
    movlw   3
    movwf   LcdY
    return;   


	end