Newhaven Display Forum

Newhaven Products => Graphic LCDs => Topic started by: Darby68 on March 02, 2018, 10:40:41 PM

Title: NHD-C12864WO-B1TFH#-M Contrast issue
Post by: Darby68 on March 02, 2018, 10:40:41 PM
Hi,

I have upgraded to this display NHD-C12864WO-B1TFH#-M because the one I was using from Newhaven was discontinued.
Its pin comparable except for the contrast section. This LCD needs a voltage divider (with a POT) to set the contrast.

Even with this setup I am having issues with the contrast, its very eratic.

Looking at the spec sheet it says that the Logic voltage should be 3.3V (I have this), now the JST connector that powers
the LED white backlight needs to be 3.4V to 3.6V, I hooked this up to my powersupply and this is fine. However there is
an Item in the spec sheet that says "Supply for LCD (contrast)" Vlcd page 5 of the spec sheet, it says 9.2V to 9.8V and on page
3 of the mechanical diagram it says Voltage 3.0V VDD, 9.5V VLCD. Where is the hookup for VLCD? IM confused that should be 9.5V?

Any help would be appreciated.

Thanks
Title: Re: NHD-C12864WO-B1TFH#-M Contrast issue
Post by: Saurabh_B on March 05, 2018, 08:02:47 AM
Hello,

The VLCD is generated by the booster circuit on the display and is controlled via software (Set Electronic Volume Command)
This voltage doesn't need to be applied, and you should see 9~11 V on pin V0 if your settings are correct and the internal booster is activated.