lcd-09568 character blocks on all the time

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Berny

Member
Greetings all,
I recently got my LCD-09568 from Sparkfun and had it working fine until I did "something", I know not what and now the character blocks are on all the time. I have read some posts regarding this LCD display but have been unable to make those pixel boxes "invisible" like they were when I first got the module. I am using a 08M2 with a baudrate of T9600_8. I read the datasheet for the LCD but, as I said, been unable to return the display to its "original" state.
I have been working on this for 2 days now and am getting a bit irritated. It is now 17:55 hrs here on the golden gulf coast of Texas.

Thanks,
Pat
IM000759.JPG
 
W

westaust55

Moderator
Is there a trim potentiometer for contrast. The darker blocks in every character cell suggests that the contrast needs to be turned down.

It is good practice to give a link to the datasheet for items so that others do not have to gos earching for information to help you.
In other words, help folks (by providing sufficient information) so they help you
 
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nick12ab

Senior Member
You putting the word "something" in quotation marks makes it sound like you've done something wrong like connecting too high a voltage or connecting the supply backwards. From what I can see, the blocks look too faint to just be an issue with the contrast setting if no text appears on-screen and it also looks like they're flickering too - this usually means you've blown it. However before you give up look on the back of the LCD module and check that you haven't knocked off any of the SMD components, especially the frequency set resistor and capacitor.

Addition: the product page shows an image of the LCD with a small potentiometer that looks the same as the one WestAust pointed out on the back in the opposite corner to the microcontroller. Try adjusting that.
 
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S

srnet

Senior Member
It worked fine until you did "something" ????

Well ?

It has a splash screen that should appear at power up, and only the power needs to be connected, no connections to the PICAXE needed.

So with only the power connected do you get the splash screen ?
 
W

westaust55

Moderator
If the LCD module is working correctly, theSplash screen is displayed for 0.5 seconds unless . . . the command has been sent to toggle it off.

Some "thinking out loud" here:
While not a guaranteed case, believe LCD modules only show blocks in the top row of the display when the power is applied until the display is initialised.

From recollection the Sparkfun uses True and not iNverted serial data - is this the case? (I don't have one to test)
This would need a baud rate parameter commencing with "T" not "N"
Could result in garbage or blocks to be continuously "accepted" and displayed filling the screen.
 
B

Berny

Member
Thanks for the replies.
I did not link to the datasheet but the LCD-09568 takes me to the Sparkfun page, and others, where the datasheet is available. I will remember to link to the datasheet in the future. The picture of the module and what I have are far different. I should have taken a picture of the back of the module also. I think I saw that the picture was from 2006.
The "something" just meant it was working correctly and now isn't as far as the overdriven display goes. I can still write text to it and it functions using the T9600_8 as I mentioned.
The splash screen does not come up anymore and I have been unable to get that fixed also. I have tried the serout 0,T9600_8,(124,9) toggle as mentioned in the datasheet but can't get the splash screen back.
I do now see the tiny potentiometer and will try adjusting that as soon as the workday is over.
 
B

Berny

Member
Couldn't wait till the workday was over. I adjusted the contrast pot and IT'S FIXED. I still have no idea how the pot got changed. I was too busy looking for a software solution and should have read the datasheets more closely. Thanks for the great advice.

Happy Camper!
 
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