LCD connections

rosco · Joined: 14 Jul 2004 Posts: 3 Location: UK

Hi,
I have a PCB with the LCD R/W line connected to a Port pin. It is used in 4bit mode. Is there a way to reset this Port pin (R/W = 0) before attempting to perform the Config Lcd function so that it will work ok? It works fine with the R/W line hardwired to 0v.

I need to do this to avoid cutting tracks. Crying or Very sad

Regards Ross

Vilko · Posted: Thu Jul 15, 2004 7:18 am Post subject: How about

Hi,

Well how about

portpin = 0

if it does not work, then simply hard connect R/W to GND, it will not harm portpin at all. (I think)

Vilko

rosco · Joined: 14 Jul 2004 Posts: 3 Location: UK

Thanks Vilko

I have allready tried that, both as a BASIC and assembler command but neither work.

I think the compiler must perform the "Config Lcd" first and then sort the rest of the code.
If I connect my scope to the LCD E & R/W pins I can see the E line active high pulses before the R/W line is driven low, allthough the instruction to reset the portpin is placed before the "Config Lcd".

You are right though, it is probably ok to tie the pin to ground, especially if I reset it in my program. It is only like using it as an input.

Ross

albertsm · Joined: 09 Apr 2004 Posts: 5925 Location: Holland

Set the pin to 0, and use LCDINIT command to re-init the display.

rosco · Joined: 14 Jul 2004 Posts: 3 Location: UK

Thank you Mark, I knew I had seen a way to do it. Just could not remember where!

As usual a case of RTFM. (Read The Flipping Manual).

Regards Ross