LCD cable length?

[Art]

Thanks guys
Didn't want to do the wiring, but should have at least searched!

[Art]

It's a VFD display with the standard LCD controller.



It's working with one metre of cable, but a bit hit & miss.
No garbled text, but sometimes it doesn't come on at all.
Maybe it just needed a longer startup time than the usual PAUSE 1000.
Ideally, I want about five metres of cable length, so I'll keep reading!

[Darrel Taylor]

In the thread where we ran them on 25/40ft cables, the LCDOUT library routines were over-ridden so the timing could be changed.

Normally, the LCDOUT command gives a 1uS pulse on the enable line.
But as the cable gets longer, 1uS isn't enough.
I used 5uS for the 25 ft length, which seemed to overcome the rounding off of the waveform on a scope.

You might try using the routines from that thread with the modified timing.
Essentially, it's the LCD_AnyPin routines with a few modifications.

[Art]

Will do, thanks
I think I'll have to.

[Art]

A little problem...
Installed the hijack routines and the two files in PBP directory.
When I use the include file for lcdanypin, I get an error (using MPASM)
for line 87 which is this line:
LOW LCD_RS : HIGH LCD_E

If I comment that out I then get a lot of errors

[Darrel Taylor]

LCD_RS and LCD_E should be declared in your program, along with the other LCD pins.
Something like ...

;----[ Change these to match your LCD ]--------------------------------------- 
LCD_DB4    VAR PORTA.0 
LCD_DB5    VAR PORTB.3 
LCD_DB6    VAR PORTB.7 
LCD_DB7    VAR PORTC.1 
LCD_RS     VAR PORTD.4 
LCD_E      VAR PORTA.1 
LCD_Lines  CON 2 ' # of Lines on LCD, 1 or 2 (Note: use 2 for 4 lines) 
LCD_DATAUS CON 50 ' Data delay time in us 
LCD_COMMANDUS CON 2000 ' Command delay time in us 
INCLUDE "LCD_AnyPin.pbp" ; *** Include MUST be AFTER LCD Pin assignments ****

[Art]

Oops!