Urgent - My LCD fills up with blocks

[Spadez]

Hi.

Im having problems with my LCD. It seemed to work perfectly, but now Im having issues with it having now properly tested it. I have two 16x2 LCD's and they both do the same thing. I plug the board in, and it seems to work to start with, but then the lcd just fills up with solid blocks. It does this one block at a time, and sweeps across the top row, then fills up the bottom, until the entire LCD is filled up with solid blocks.

What causes an LCD to do this, code, lack of power? dataline connection, rs/e connection?

This is for my Uni project which is to be handed in at the start of next week. Please please please help.

James

 

[BrownOut]

I would try re-flashing your uP. Maybe your program was corrupted.

 

[Spadez]

I can verify that the pic is fine, it works on my breadboard. I really need to know exactly what causes an LCD to do this so I can isolate the problem.

 

[Spadez]

Ive tried on a totally different LCD and it just spits out blocks still. Does nobody know what causes LCD's to do this?

 

[BeeBop]

Ive tried on a totally different LCD and it just spits out blocks still. Does nobody know what causes LCD's to do this?

Sounds like you need to adjust the contrast on the LCD, or the LCD is not initialized correctly. Probably just the contrast voltage, though.

 

[Spadez]

No it can't be because I see text fine initially, then the blocks come in afterwards.

For example, "ready" would display fine, then the blocks would come in and overright the existing content.

 

[BeeBop]

How are you setting the contrast voltage? If you are using a trim pot try adjusting it just a bit after the block show up....

Perhaps someone else has an idea?

 

[davenn]

still sounds like the mPU to me as i see the same fault with equip I service on an almost daily basis
and EVERY time its the mPU that needs reflashed

Dave

 

[Spadez]

It was the mcu programming incorrectly. Thank you!