I am trying to setup a 4x40 display. My understanding is that it functions like 2 - 40x2 displays.
Using the LiquidCrystal library it uses the 4 bit mode instead of the 8 bit mode.
Should I have wired the unused inputs on the display to ground?
At present all I get is both halves of the display the upper line is all solid blocks, and the second line is blank.