In the sparkfun project book I have students working on Circuit 4A Hello World. Using the code provided and the circuit provided we can’t get the LCD display to post text. It lights and gets power. I have triple checked the circuit and have switched out all the components and get the same thing. We have prototyped it in Tinkercad and Tinkercad shows the screen is getting to many amps. We put in a resistor and it displays the text. Try this on our physical circuit and still nothing. We are using a LCD screen with Ver 2.1 on the back, it has all 16 pins on the back.
The screen we are using is a 1602A-4 16x2
Can you post photos of the back of your screen and your setup?