How to use underlines on VFD display?

Other Hardware Displays
1

I have a Noritake CU20025ECPB 20x2 VFD display connected to my Arduino. It works just fine with the liquidcrystal library, and does everything I would expect an LCD to do. However, part of the reason I thought this display was so cool was that it has a little line under every character. I know that these do light up, because there is a little three-pin jumper on the display (not sure what it is) and when you ground the middle pin the display goes into some kind of demo mode where the underlines illuminate. I just don't know how to light them up from software.

Can anyone help me out with this?
Thanks,
Will

2

I just don't know how to light them up from software.

As far as I can tell you can only achieve this when you are creating one of the eight available user definable characters.

Don

3

OK Don,
How do I create custom character with an underline?

Also, I figured out that you can do lcd.cursor and lcd.noCursor to enable the line, but only at the current cursor position.

EDIT:
OK Don, I didn't realize that custom characters were 5x8 instead of 5x7. The following character IS a persistent underline, however it does not allow you to underline text.

byte newChar[8] = {
  0,0,0,0,0,0,0,
  B10000
};
4

Standard HD44780 LCDs have underlines (8th row) too - it's just that people don't normally use that functionality for anything.

As far as I know too - the only way you can underline is with the underline cursor (one character) or with custom characters (up to 8 custom characters with underlines).

If you wanted to define a whole new character set in code then it appears from earlier discussion that you can change custom characters without the ones already written to the display changing - this means you could define and use custom characters 'on the fly' and have as many as you like.

5

mowcius:
Standard HD44780 LCDs have underlines (8th row) too - it's just that people don't normally use that functionality for anything.

As far as I know too - the only way you can underline is with the underline cursor (one character) or with custom characters (up to 8 custom characters with underlines).

If you wanted to define a whole new character set in code then it appears from earlier discussion that you can change custom characters without the ones already written to the display changing - this means you could define and use custom characters 'on the fly' and have as many as you like.

Cool, never knew that...

6

Cool, never knew that...

Me neither - I haven't tried it yet so I can't guarantee it works or maybe it only works on some displays - dunno.