Code that worked with WINDSTAR LCD doesn't work with Newhaven LCD?

[jellis00]

Also could be as simple as a contrast voltage issue (Vo). Do you have a pot on the Vo pin?

Also noticed pin 15 and 16 of the New Haven display are listed as NC in the data sheet, but the example schematic shows them as A+ and K- and shows then both grounded. So maybe you need some clarification from New Haven on how to connect up the display.

Yes, I have a 20K ohm potentiometer connected as a Vo source for controlling contrast. I see the black matrix dots on the 1st line of the display when I power up with the pot set near 0 ohms....that is how Newhaven said I could tell if the LCD is alive and well and hasn't been zapped.

You are right, that on the prototype PCB pins 15 and 16 are connected to ground...did that because that is wn on scheamtic on Page 4 of the LCD data sheet.....but we checked with Newhaven tech support and they said it doesn't make any difference whether pins 15 and 16 are grounded or left un connected for this particular module that doesn't have a backlight.

Thanks for the comments, anyway...they help me keep thinking.