Drive Character LCDs From Arduino With GCBASIC: A Maker's Guide

The Setup

Character LCDs are everywhere in maker electronics. They show temperature readings, filament counts, menu options, and error codes on 3D printer builds, CNC machines, and custom automation projects. Getting one to work reliably from an Arduino used to mean wrestling with the LiquidCrystal library in C++. Chuck from CHEP's Filament Friday series demonstrates a cleaner path: GCBASIC, a compiler that wraps the same low-level LCD commands in a syntax closer to classic BASIC.

The basic wiring is unchanged from any standard HD44780-based display. A 16-pin character LCD connects to the Arduino through eight data lines plus RS, EN, and RW control pins. The GCBASIC compiler then handles the initialization sequence, cursor positioning, and character writes through straightforward keywords rather than function calls with multiple arguments.

Why GCBASIC Over C++

The main advantage is readability for makers who are new to programming. A GCBASIC LCD setup script reads almost like plain English. You declare the pin connections at the top, call an init routine, and print text with a single PRINT statement. That structure makes debugging easier because the program flow is visible at a glance.

Performance-wise, GCBASIC compiles down to native AVR machine code, so display updates run at the same speed as equivalent C++ code. The difference is purely in how the source looks. For a display that refreshes a few times per second, the compiler choice makes no measurable difference to the end user.

Practical Applications for 3D Printers

Replacing a stock printer display with a custom Arduino-driven LCD opens up a lot of possibilities. You can show bed temperature, layer progress, estimated time remaining, and filament runout warnings on a panel of your choosing. The GCBASIC approach is especially useful when you are building a custom control box or adding a secondary status display to an existing printer without touching the mainboard firmware.

Chuck's video walks through a working circuit on camera, showing each wiring connection, the GCBASIC source file, and the compiled result running live. He also covers common failure modes: contrast adjustment with the potentiometer, backlight power considerations, and dealing with the LCD's busy flag when reading from the display.

Getting Started

If you already have an Arduino and a character LCD lying around, this is a twenty-minute project. The hardware costs nothing if you scavenge from old electronics. The GCBASIC compiler is free and integrates with the standard Arduino IDE workflow. The full walkthrough is available on the CHEP Filament Friday channel, and the source code is linked in the description.