Vladimir M. Klochko wrote:-
     
     
    Steve insert NOP's after BSF LCD_CNTL,E. These *may* be
unnecessary. Using short cable 4MHz PIC and LCD (I'd use 4-bit 
mode too) work without these NOP's according to datasheet and 
experiment. But when the cable length is about 30..50cm or 
greater (I mean usual ribbon cable) LCD's outputs can't drive 
long cable's capacitance and need extra time to recharge it. 
NOP's provide this time.
     
     Reading from the Hitachi HD44780U Data Sheet, (sept '93) the time from 
     "enable high" to valid data out can be upto 360ns. (clone chip are 
     slightly faster)
     
     More importantly, The PIC data states:-
     "5.3.2 SUCCESSIVE OPERATIONS ON I/O PORTS
     The actual write to an I/O port happens at the end of an
     instruction cycle, whereas for reading, the data must be
     valid at the beginning of the instruction cycle (Figure 5-5)."
     
     This is why I insert "nop"s 
     
     Steve Lawther