Re: Still Not Working

Arv Evans

Curt and David

I get that when the Arduino has not fully initialized the LCD display.  It can be caused
by the RE or EN lead not making good contact.  I have this sometimes when using a
prototype plug-board for temporary layouts.

Is there any back light on in the LCD?  Has it ever worked properly?  Does the tuning
adjustment work? 

I doubt that this is an LCD problem or a problem with software or the Raduino board. 
Most likely it is a wiring situation...but I have been wrong before.

This is what happens when power is applied to the LCD but no subsequent commands
are sent to the display to initialize it for 2 lines by 16 characters.  I made this happen
by lifting the LCD's RE lead from its connector.

There are 2 control lines (RE and EN) along with 4 data lines (D4,5,6,7) sent to
the LCD.  There are also +5V power and ground on the two pins on one end.  The
two pins on the opposite end need +5 through a small resistor and ground for the
backlight LED.  A look at the schematic for the Raduino will show which pins connect
to what between Raduino and the LCD.

It should look something like this, but with the normal Radiuno text on the LCD.

Yes, I know those are poor quality pictures, but its the best I can do with sunlight
streaming into the room. 

The contrast control potentiometer can change whether the boxes are shown as
black or white on the back light background.


On Fri, Jul 14, 2017 at 2:01 PM, Curt M. <Kc3hjp@...> wrote:
Have any of you guys seen this where the display shows black boxes all the way across the top line of the display?

Join to automatically receive all group messages.