LCD Screen Not lighting

EddieB · Post by **EddieB** » Fri Feb 02, 2007 8:25 pm

Hello,

As you may have noticed from the large amount of post's I have created lately, I have just purchased the multiprogrammer and flowcode3. Although I already had an LCD screen and prototypeboard, I bought these from a different site ( elektor eletronics I think ) about a year ago, and wasn't familiar with eblocks at the time.

Now, I am working in low voltage mode with a 16F88 and my LCD screen is connected to port B. I have a wire going from the +V on the board, to the +V on the LCD board. I have ran all the different flowcode programs for LCD's, but my LCD board seems to be doing nothing, Im seeing now signs of it working. I have adjusted the contrast but it seems nothing is going "Trough it".

Ive only used the board once, and it was connected correctly to a 5v dropper. It has been sitting in my cupboard since last year.... Are there any tests I can perform to see if my LCD boars is "still alive"?

Many Thanks,
Eddie

Mark · Post by **Mark** » Sat Feb 03, 2007 5:02 pm

Eddie,

I think LVP mode uses RB5, which is needed for the LCD (change jumper after programming?). Personally if you have the multiprogrammer board then I would forget LVP unless there is agood reaon in an end use application.

Hope this hlps,

Mark

EddieB · Post by **EddieB** » Sat Feb 03, 2007 6:06 pm

Mark,

I only have a 12v dropper, and they say 13.5v, Will this be okay?...

Cheers

EddieB · Post by **EddieB** » Sat Feb 03, 2007 7:41 pm

Well, ive been playing with this a bit...

Im using the flowcode3 hello world lcd example with HS,XTAL clock settings... ( Im also using an external powersupply... )

All I am seeing is 8 blocks top and bottom filled in black, im not seeing my hello world.

Any help?

Cheers

Post by **Benj** » Mon Feb 05, 2007 11:13 am

Hello EddieB

Sounds like the LCD is not being initialized. You need to confirm that

a)your PICmicro is running correctly eg correct oscillator mode and watchdog off.

b)The portB is behaiving as expected. Eg pins all set to digital I/O and not LVP / Alternatively you could use a different port eg C or D with a larger PICmicro.

EddieB · Post by **EddieB** » Mon Feb 05, 2007 6:39 pm

I have checked port B and everything is functioning correctly, although it displays 8 blocks and nothing changes... The only time I see not "action" is when I have the 5v connected from the board to the lcd.

Cheers

Post by **Benj** » Tue Feb 06, 2007 10:54 am

Hello Eddie I have sent you some test programs let me know how they work out.

EddieB · Post by **EddieB** » Tue Feb 06, 2007 7:31 pm

Hello Ben,

Sorry for the inconvenience, but I no longer use the email address in my profile, although I have just changed it to my current one.

Could you please forward the email to that account so I can use it on this PC?

Cheers

EddieB · Post by **EddieB** » Tue Feb 06, 2007 8:31 pm

Hello again,

There is no need to send me the email now, I have tested them. I do not have an LED block yet, but I connected up a 7 seg display I found, and they all light up and blink at a perfect interval!

So thats working... But when I tried the LCD one, 8 blocks light up for a millisecond then disappear, no message is visible. So I think the chances our high that it is faulty... I have had it for a year and haven't used it since... And I did not purchase it from matrixmultemedia.

Cheers

EddieB · Post by **EddieB** » Fri Feb 09, 2007 5:55 pm

Another update:

I have made a program like this:

While 1

Out 255 port b

delay 25 ms

Out 0 port b

Delay 25 ms

End while

This gives me only 8 solid blocks on the lcd screen

Hmm..

Cheers

EddieB · Post by **EddieB** » Wed Feb 14, 2007 8:32 pm

Hello,

I have recently purchased the 16F877A chip which alows me to use all 5 ports.. I have tried the LCD screen on each port with 5v+ on the lcd screen...

A bit of improvement; The LCD screen shows all 16 blocks now, but doesnt display anything...

Cheers

Mark · Post by **Mark** » Fri Feb 16, 2007 12:44 pm

Eddie,

Sorry it is not clear to me if you are using the LCD E-block. If you are not then a problem can be that the contrast setting for the LCD may need adjusting. It is possible for an LCD to be working perfectly well but you see nothing unless contrast is correct, do this by using a potentiometer and adjusting it to see what happens.

Also do not forget to place a seperate flow box with LCD-Start and preferably LCD-Clear after it otherwise nothing after it will work.

Hope this helps,

Mark

EddieB · Post by **EddieB** » Fri Feb 16, 2007 4:45 pm

Hello Mark,

I have done all this the LCD e-block refuses to work as it should, so I have sent it back and should be getting a new one soon

Cheers