Standard HD44780 LCD

I ordered a standard HD44780 LCD:

https://core-electronics.com.au/assembled-standard-lcd-16×2-extras-white-on-blue.html

HD44780 datasheet with the detailed commands for control

a datasheet that has dimensions and pin-locations

So I started to follow:

https://learn.adafruit.com/character-lcds

Step one was to wire up the display just to power. So I connected 3.3V pin from the Esp32-S2 Wroom to pin 15 on the display. Importantly, you’ll note that the ESP32-S2 power is 3.3V which is enough to power the display but only just! I also connected the ground pin from the ESP32-S2 to Pin 16 on the display. This is just the power to the back light of the display.

The next step was to insert a POT (variable resistor to control the brightness of the actual display items) but when I did that turning the POT made no difference.

I deduced that the issue was that 3.3V input from the ESP32-S2 wasn’t high enough. Thus, I connected up my external battery pack, which outputs 4 x 1.5V = 6V and as you can see from the above when I twist the POT (i.e. a variable resistor) I can now see the lines of rectangle display items actually appear.

Thus, the display is all wired up for power, backlight and character display, now I just need to wire it for data and do some code.

The wiring diagram is shown above: