Pcf8574 i2c lcd

[cesar35]

Hi, thanks for the reply
I made a correction on the LCD pins now it is working
More being stays on too long the display stays as mixed characters

LCD_BuffSize    CON 30
LCD_Buff        VAR BYTE[LCD_BuffSize]
LCD_BuffAddr    CON EXT : @LCD_BuffAddr = _LCD_Buff
LCD_BuffLen     VAR WORD        ; Length of data in buffer
LCD_Data        VAR BYTE        ; Data to Send to LCD
LCD_Byte        VAR BYTE        ; Nibbles to Send
LCD_RS          VAR LCD_Byte.0  ; Register Select bit
LCD_RW          VAR LCD_Byte.1  ; Read/Write bit
LCD_E           VAR LCD_Byte.2  ; Enable bit
LCD_BackLight   VAR LCD_Byte.3  ; Backlight 0=ON
LCD_WriteMode   VAR BYTE        ; 1=LowNibble, 2=HighNibble, 3=Both
LCD_CommandMode VAR BIT         ; Indicates next byte is a command
LCD_Byte2       VAR BYTE        ; Same nibble without E bit
LCD_Idx         VAR BYTE
testmode        var byte

GOTO Over_LCDPCF8574 

;----[Write 1-byte to LCD]--(Input is LCD_Data)---------------------------------
USERCOMMAND "LCD_WRITE"
LCD_WRITE_:
   LCD_E = 1
   IF LCD_WriteMode.1 = 1 THEN                            'Write High Nibble
     LCD_Byte = (LCD_Byte & $0F) | (LCD_Data  & $F0)
     LCD_Byte2 = LCD_Byte & $FB    
     I2CWRITE SDA,SCL, LCD_Addr,[LCD_Byte, LCD_Byte2]
   ENDIF
  
   IF LCD_WriteMode.0 = 1 THEN                             'Write Low Nibble
     LCD_Byte = (LCD_Byte & $0F) | ((LCD_Data << 4 )& $F0)
     LCD_Byte2 = LCD_Byte & $FB
     I2CWRITE SDA,SCL, LCD_Addr,[LCD_Byte, LCD_Byte2]
   ENDIF
return

ASM
LCD_WRITE?  macro
    L?CALL _LCD_WRITE_
  endm
ENDASM

;----[Write contents of buffer to LCD]------------------------------------------
USERCOMMAND "LCD_WRITEBUFF"
LCD_WRITEBUFF_:
' The purpose of this routine is to increment through LCD_Buff and
' pass each character to LCD_Data so that it can be written.
' This will loop for LCD_BuffLen which is calculated by 
' subtracting the starting address of the buffer from the
' ending address of the buffer.

    LCD_BuffLen = R5 - LCD_BuffAddr -1
    LCD_WriteMode = 3          ; Both Nibbles
    LCD_CommandMode = 0
    FOR LCD_Idx = 0 TO LCD_BuffLen
        IF LCD_Buff(LCD_Idx) = $FE THEN LCD_CommandMode = 1 : GOTO LCD_ByteDone
        IF LCD_CommandMode THEN
            LCD_RS = 0   ' this is a command
            LCD_CommandMode = 0 ' false, next byte will be data
        ELSE
            LCD_RS = 1   ' this is data
        ENDIF
        LCD_Data = LCD_Buff(LCD_Idx)
        LCD_Write
        IF LCD_CommandMode THEN
            PAUSE 2
        ELSE
            PAUSEUS 50
        ENDIF

      LCD_ByteDone:
    NEXT LCD_Idx

    LCD_CommandMode = 0
RETURN

ASM
LCD_WRITEBUFF?  macro
    L?CALL _LCD_WRITEBUFF_
  endm
ENDASM

Over_LCDPCF8574:

;----[Initialize the LCD]-------------------------------------------------------
PAUSE 250             'LCD Power-on delay
LCD_Backlight = 1     'Backlight OFF
LCD_RW = 0            'Write to LCD
LCD_RS = 0            'Command Register

LCD_WriteMode = 1     '-- Low Nibbles only
LCD_Data = 3          'Reset 3 times
gosub LCD_Write_
PAUSEUS 6000
gosub LCD_Write_
PAUSEUS 1000
gosub LCD_Write_
PAUSEUS 1000

LCD_Data = 2          ' Start 4-bit mode
gosub LCD_Write_
PAUSEUS 1000

LCD_WriteMode = 3     '-- Both Nibbles
LCD_Data = $28
gosub LCD_Write_      'Function Set, 4-bit, 2-line, 5x7
LCD_Data = $0C
gosub LCD_Write_      ;Display ON
LCD_Data = $01
gosub LCD_Write_      'Clear Screen
PAUSE 2
LCD_Data = $06 
gosub LCD_Write_      'Entry Mode
                       
PAUSE 2               ; Let command finish