Newhaven 4x40 LCD, issues!

[Christopher4187]

The issue ended up being a capacitor on the demo board. I'm assuming that the rise time for the data lines wasn't quick enough. The other thing I've learned is, this LCD does not have contrast control and therefore Vo does not exist on this screen. Seems strange but that's why pin 3 is listed as N/C.

Darrel, this program is awesome. You deserve a raise!

[MOUNTAIN747]

Christopher, pin 3 is DB5, pin 16 is NC. If you have a 20k pot center taped to Vo you should have contrast. I can vary the contrast on my 4x40 over about a turn and a half of the pot. It goes from almost no visible characters to bright characters. Look over your Vo hardware once more.

Wayne

[Christopher4187]

Christopher, pin 3 is DB5, pin 16 is NC. If you have a 20k pot center taped to Vo you should have contrast. I can vary the contrast on my 4x40 over about a turn and a half of the pot. It goes from almost no visible characters to bright characters. Look over your Vo hardware once more.

Wayne

You have an LCD screen. I have an OLED screen ( I know I put LCD above but it was a mistake). Pin 3 for me is no connection. Putting a POT on pin 3 does nothing. Again, this board does not have a Vo pin.

I suppose you could adjust the contrast by lowering the input voltage if it's really necessary.

[MOUNTAIN747]

Wow, I totality missed that. My apologies, I was a bit too energetic to help and failed to read your first post closely. Glad you got the OLED working. It's a good looking display!

[Christopher4187]

No worries. I'd prefer someone be too energetic to help than not help at all.

[jmgelba]

I have a Newhaven display here with the ST7066U driver. It doesnt work, nor did its replacement. I then went to an Optrex and plugged it into my connector, and it worked right away. Coincidence? Either way, could you guys confirm that a ST7066U driver works?

Thanks.

[MOUNTAIN747]

Jmgelba,
Just a suggestion, try using the above Newheaven_4x40_Text Code.txt , INIT_LCD rutine and its sub’s, EEPRON, and E1 variable. This routine is for a duel ST7066U so you should only use Command1 in INIT_LCD. After initializing the LCD, all PBP commands should work. As stated in above post’s Vo adjustment must be made to find the sweet spot to display. Good luck!

Wayne