' =========================================================================
' File: LCDDEMO.BS2
'
' BASIC LCD demonstration
' Ver 1.1 - Updated to conform to BS2p LCD connections
' =========================================================================

E		CON	1                       ' LCD Enable pin  (1 = enabled)
RS		CON	3			' Register Select (1 = char)
LCDout	VAR	OutD				' 4-bit LCD data

ClrLCD  	CON	$01                     ' clear the LCD
CrsrHm  	CON	$02                     ' move cursor to home position
CrsrLf  	CON	$10                     ' move cursor left
CrsrRt  	CON	$14                     ' move cursor right
DispLf  	CON	$18                     ' shift displayed chars left
DispRt  	CON	$1C                     ' shift displayed chars right
DDRam   	CON 	$80                     ' Display Data RAM control
 
char    	VAR 	Byte                    ' character sent to LCD
index   	VAR 	Byte                    ' loop counter

' -------------------------------------------------------------------------

Msg     	DATA	"THE BASIC STAMP!",0	' preload EEPROM with message

' -------------------------------------------------------------------------

Initialize:
  DirL = %11111001				' setup pins for LCD
  DirH = %11111111
  GOSUB LCDinit					' initialize LCD for 4-bit mode
' ------------------------------------------------------------------------
END
Main:
  char = ClrLCD					' clear the LCD
  GOSUB LCDcommand
  PAUSE 500
  index = Msg					' get EE address of message

ReadChar:
  READ index, char					' get character from EEPROM
  IF char = 0 THEN MsgDone			' if 0, message is complete
  GOSUB LCDwrite					' write the character
  index = index + 1				' point to next character
  GOTO ReadChar					' go get it
MsgDone:						' the message is complete
  PAUSE 2000					' wait 2 seconds

  char = CrsrHm					' move the cursor home
  GOSUB LCDcommand 
  END

' -------------------------------------------------------------------------

LCDinit: 
  PAUSE 500						' let the LCD settle
  LCDout = %0011					' 8-bit mode 
  PULSOUT E,1
  PAUSE 5
  PULSOUT E,1
  PULSOUT E,1
  LCDout = %0010					' 4-bit mode
  PULSOUT E,1
  char = %00101000				' 4 lines
  GOSUB LCDcommand
  char = %00001111				' disp on, crsr off, blink off
  GOSUB LCDcommand
  char = %00000110				' inc crsr, no disp shift
  GOSUB LCDcommand
  char = %00000001				' cls
  GOSUB LCDcommand
  char = "C"
  GOSUB LCDwrite
  char = "h"
  GOSUB LCDwrite
  char = "r"
  GOSUB LCDwrite
  char = "i"
  GOSUB LCDwrite
  char = "s"
  GOSUB LCDwrite
   
RETURN


LCDcommand: 
  LOW RS					' enter command mode
  LCDout = char.HighNib				' output high nibble
  PULSOUT E,1					' strobe the Enable line 
  LCDout = char.LowNib				' output low nibble
  PULSOUT E,1
  HIGH RS
  RETURN					' return to character mode

LCDwrite:
  LCDout = char.HighNib				' output high nibble
  HIGH E
  LOW E
  LCDout = char.LowNib				' output low nibble
  HIGH E
  LOW E
  RETURN