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Topic: Help w/ Display (Drivers SPLC780D OR ST7066U) (Read 348 times) previous topic - next topic

Peter9DO

I have just recently purchased some displays from New Haven Display and the drivers listed are SPLC780D OR ST7066U, from doing some reading prior to purchase, I saw that it is compatible to the Arduino because it's the same coding for the HD44780 driver (if I worded that incorrectly I apologize). I had a sketch running already that had a HD44780 screen on it and wanted to change the screen out to this new 4x20 display I purchased (NHD-0420AZ-FL-GBW-3V3). When I hooked it up, to no surprise it was NOT working properly. I tinkered around a little, did some reading (which has confused me more) and here I am!

To make this easier, I'm working off of the "Hello World" sketch which has the pin out as follows:
* LCD RS pin to digital pin 12
* LCD Enable pin to digital pin 11
* LCD D4 pin to digital pin 5
* LCD D5 pin to digital pin 4
* LCD D6 pin to digital pin 3
* LCD D7 pin to digital pin 2
* LCD R/W pin to ground
* 10K resistor:
* ends to +5V and ground
* wiper to LCD VO pin (pin 3)

The display is on, and working it just has symbols and blacked out segments...

Here is the datasheet from the LCD display:
http://www.newhavendisplay.com/specs/NHD-0420AZ-FL-GBW-3V3.pdf

Any help would be much appreciated!  If I can supply any additional information please let me know what you need. Thank you in advanced for your help!

Pete
What if Burt Reynolds, really changed his name to Turd Ferguson?

floresta

According to the data sheet that you linked to this is a 3.3v device.  Have you taken that into account?

Don

Peter9DO


According to the data sheet that you linked to this is a 3.3v device.  Have you taken that into account?

Don


Yes sir.
What if Burt Reynolds, really changed his name to Turd Ferguson?

floresta

You aren't providing much information.  Are you sure that the current drain of the backlight isn't causing your supply voltage to sag?

Don

Peter9DO

Yes, Voltage is good. The display is working fine, it's just displaying random nonsense. What information could I provide you that would help with diagnosing the issue? I really do appreciate your help on this!
What if Burt Reynolds, really changed his name to Turd Ferguson?

Peter9DO


You aren't providing much information.  Are you sure that the current drain of the backlight isn't causing your supply voltage to sag?

Don


I thought about this a little more, I have a regulator circuit on this to step down to 3v... Now, it's working perfect! Well other than I had to change the resistor on the contrast. When I have the LCD on the text disappears and when I have it off it works fine. I have to find the right resistance that will work for both. Not really a big deal. Thanks for the help Floresta!
What if Burt Reynolds, really changed his name to Turd Ferguson?

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