Hello John,

I noticed that you do a swap on PORTB. IMHO that would not be possible.

Here is snippet of code that works fine in several applications I have.

; Before writing tot the LCD check if busy
; This routine returns only when LCD BUSY flag is clear
; and has the current DD-RAM address in TEMP.
; (for 4 MC XTAL; E should be active for min 480 nsec is less than 1 cycle)

;

CheckLCDBusy
           bcf     PORTA, LCD_RS_BIT    ; command mode so RS bit 0
           bsf     PORTA, LCD_RW_BIT    ; we are going to Read so RW bit 1
           movlw   b'11111111'          ; set PORTB for input
           tris    PORTB                ; the quick an dirty way
Read_Busy
           bsf     PORTA, LCD_E_BIT     ; switch the Enable bit on
           movf    PORTB, W             ; read the port with leaving a working copy in W
           movwf   TEMP                 ; save LCD data addresd in TEMP
           bcf     PORTA, LCD_E_BIT     ; switch E-bit off
           andlw   b'10000000'          ; is bit 7 (busyflag set?)
           skpz                         ; if busy flag is cleared then skip
           goto    Read_Busy            ; keep reading till cleared
           bcf     PORTA, LCD_RS_BIT    ; exit command mode = clear RS
           movlw   b'00000000'          ; and make PORTB
           tris    PORTB                ; an output port again
           bcf     PORTA, LCD_RW_BIT    ; reading done, back to write
           return                       ; with DD-RAM address in TEMP (note: BUSY Fl. cleared)