lcd 20x4 problem

[Jordy101091]

Hi,

I'm really busy with my project and made some good progress. Monday I have bought A new LCD screen for my project from Conrad.nl.

The LCD is an AV2040 with an KS0066 LCD controller ship on it. Thats the main reason I have bought it because the EB005 LCD board uses also an KS0066 controller. I have also bought an breadboard eblock for hooking up my LCD but because its not arrived yet I have solder some connections to the LCD and plug them into the EB005 Board into plug array P2, after checking all the connections and being sure everything is fine I turned the power on, you gues!

NO REACTION.

So I have checked the datasheet of the EB005 board I say that they used the connections 4-7 as the data pins. and I used 0-3 on my LCD. So after switch then to meet up with the connections of the EB005, I checked again this time there is something different.

First, only 2 rows where black (row 1 and 3)
now all rows are adjustable with the contrast pot.

So thats some of improvement.

But when I whant to display "Hello World" it goes fine on the LCD from the EB005 and not on my new LCD, some times ive got a bunch of random chars. but not all the time. I have taking a look on the two data sheets and checked maybe its a timing issue. There is some differences but I not sure that, that is my problem.

I also checked my clock setting XTAL and HS and disabled LVP also.

Hope you guys can help me.

Regards Jordy Kleian

[Benj]

Hello,

Have you tied the R/W pin to ground?

Also would you mind attaching your test program to the forums and I will have a quick look and see if there is anything potentially there causing an issue.

[Jordy101091]

Thanks for your reply,

and to answer your question; Yes I have my R/W pin grounded.
I have also tried the 4 data lines connected on Pin 7-10 but that doesn't work either. So I reconnected the data lines to Pin 11-14 of my LCD but still doesn't work. and the strange thing is that the LCD on mthe EB005 board is working correctly, I didn't now that it's so difficult to wire up this LCD screen.
I will attach my test program and upload some photos. So you can see what and how I have connected everything.


This is what I get all the time

The connections:

1:
Blue -> VEE -> +5V
Green -> VDD -> 0V
Yellow -> Vo -> Contrast

2:
Blue -> RS
Green -> R/W
Yellow -> E

3:
Red -> DATA 0
Orange -> DATA 1
Brown -> DATA 2
Orange -> DATA 3

4:
Purple -> Back-light + 4.2
Grey -> Back-light - 0



Here you can see because my eblock+breadboard is not arrived yet I hooked-up the display with the P2 connection array.



I hope you can help to get this thing to work, it was not a cheap display

Regards Jordy Kleian

[Benj]

Hello Jordy,

It looks to me like your display is not being initialised so I would try the following:

Have you tried removing the jumper from the LCD E-block. The fact that you have two displays connected to the same output may have something to do with the problem. Removing the jumper should essentially disconnect the E-blocks display.

How are you controlling the contrast pin? are you using a potentiometer or simply a potential divider circuit using 2 resistors?

The fact that your E-blocks display is working means that you probably have your configuration and clock speed setup correctly in Flowcode. I've also had a look at your flowcode file and your settings look ok to me.

The only other thing I can think of is if the wires plus the breadboard plus the more wires are causing the signals to be attenuated or pick up noise before they get to the display. This shouldn't be the case but it can happen.

Let us know how you get on.

[Jordy101091]

To answer your questions first:

1. Yes I have tried to remove the jumper but no succes.
2. I'm controlling the contrast via an Pot. meter.

What I have done, I thought about it because you said:

The only other thing I can think of is if the wires plus the breadboard plus the more wires are causing the signals to be attenuated or pick up noise before they get to the display. This shouldn't be the case but it can happen.

I have soldered an D9 connector to the data lines of my LCD and plug them into my PortB of my EB006 board. then disconnected from my power supply and hokked it up to the connection terminals GND and V+ of the EB006 board.

Apply power to the board and what do you think, the display is working correctly.

Here are some pics.






Thanks for your reply a appreciated it, thank you.

Regards Jordy Kleian