GPU12864

VidiaG Force RT-X12864

VidiaG Force RT-X12864 is an open-source, microcontroller-based GPU designed for 128x64 GLCD displays. It acts as a dedicated graphics processing unit, handling framebuffer management, rendering, and communication with the display independently from the main CPU.

Unlike a typical GLCD library, the CPU does not directly control the display. Instead, it sends high-level drawing commands to the RT-X12864 GPU, which performs all rendering operations and updates the GLCD using its own framebuffer.

Features

• Dedicated GPU architecture for 128x64 GLCD displays
• Independent framebuffer management
• I²C communication between CPU and GPU
• Text rendering with 5x7 and 8x8 fonts
• Pixel, line, rectangle, and filled rectangle drawing
• Circle and filled circle rendering
• Bitmap rendering from PROGMEM
• Open-source hardware and software
• Expandable command-based communication protocol

Architecture

CPU (Master)
    |
    | I²C Commands (400 kHz)
    v
VidiaG Force RT-X12864 GPU
    |
    | Framebuffer Rendering
    v
CustomGLCD Driver
    |
    v
128x64 GLCD Display

[!IMPORTANT] The CPU only sends high-level commands such as drawing pixels, lines, text, and bitmaps. The GPU handles all low-level rendering and display communication.

Hardware

Installation

1. Upload gpu_soft/ScreenI2C/ScreenI2C.ino to the Arduino Uno R4 WiFi.
2. Connect the GLCD display to the GPU according to the schematic.
3. Connect the CPU board to the GPU via I²C using GND, VCC, SCL, and SDA.
4. Include GPU12864.h in your CPU project.
5. Call gpuBegin() before using any GPU functions.

Basic Usage

#include "GPU12864.h"

void setup()
{
    gpuBegin();
    gpuClear();

    gpuDrawText(1, 1, "Hello, World!", FONT_5X7);
    gpuDrawLine(0, 0, 127, 63);

    gpuUpdate();
}

void loop()
{
}

Available Commands

The API is function-based rather than object-oriented.

Functions, yes, functions. Because yes.

It was simpler to implement this way. :P

[!TIP] You can use gpuFillRect() instead of gpuClear() when you want to clear only part of the screen to avoid screen flashing on refresh.

Demos

The repository includes several demonstration programs:

• Hello World
• Font rendering demo
• Shapes and primitives demo
• Sine wave graph
• Live scrolling graph
• Bouncing ball animation
• Rotating 3D cube
• Benchmark demo
• Full demonstration sequence

Arduino IDE Package

For developers who want to use GPU12864 and additional drivers without copying files into every sketch.

Download the Arduino IDE package (ZIP)

After installing the ZIP through Sketch → Include Library → Add .ZIP Library…, use:

#include <GPU12864.h>
#include <adrv/AdditionalDriver.h>

instead of:

#include "GPU12864.h"
#include "AdditionalDriver.h"

Ready-to-use sketches are available in File → Examples → GPU12864 IDE Pack.

PCB

The repository includes the complete KiCad project and manufacturing files for the RT-X12864 adapter PCB, including:

• .kicad_pro project file
• .kicad_sch schematic
• .kicad_pcb PCB layout
• Gerber files (.gbr)
• Drill files (.drl)
• gerber.zip ready for PCB fabrication

Documentation

• Technical Specification
• Bitmap Conversion and Rendering
• I²C Communication Protocol
• Additional Drivers
• Fun Specifications (Easter Egg)

Hardware Files

• Project Files
• Gerber Files
• Gerber Package

[!NOTE] This is not an RTX graphics card. It is a custom, microcontroller-based 2D GPU for GLCD displays.

This project is released as open-source hardware and software. You are free to study, modify, and distribute it under the terms of the license.