lcd 4x20 help

ptmeejl2 · Joined: 24 Nov 2008 Posts: 2

hi,

Firstly I must say I am student and only have little experience with pics, so forgive me if anything I ask is very basic and might seem obvious to all you experts out there!

I'm using a pic 18f4520 with a hd44780 compatible 4x20 lcd.

I have been trying to get the lcdflex_420 driver to work with this.
the driver compiles and builds ok. It loads to the pic and I think it's even running.

Problem is that the lcd is not displaying anything.

I'm trying to use 4bit mode. the R/W is tied to ground and the relevant line in the code is removed.

The codes seems to be working, as I have measured the pins with a scope, and they seem to be getting the right signals. There is also data on the data pins.

The only twist to this story is that I'm using a level shifter from the pic to lcd, as I run the pic at 3v. The shifter is working ok, and is doing what it should according to the scope. It's enabled at all times by grounding oe-not and dir set to one direction only.
Hoping someone can give me a pointer or 2.

Tthink it could be the initialisation, but not sure where or how.

thanks

james

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

Read this recent long thread. On page 2, it turned out to be a broken wire.
http://www.ccsinfo.com/forum/viewtopic.php?t=36759

Rohit de Sa · Joined: 09 Nov 2007 Posts: 282 Location: India

Post your code.

Rohit

ptmeejl2 · Joined: 24 Nov 2008 Posts: 2

Just to say thanks for your replies, it turned out to be a dead lcd module, changed it for another one and it works fine.

I can also confirm that the flex_lcd420 driver works with the winstar wh2004a (20x4) without modification. (other than pic specific)

Thanks pcm, hope you don't mind me using your driver. It has saved alot of time.

Thanks again for your help.

James