HUB75 Adapter Board for ESP32 and Raspberry Pi

RGB Matrix Adapter Board with Buffered Level Shifting

The RGB Matrix Adapter Board (E), Rev 2.2 is a buffered HUB75 adapter board for connecting 3.3V logic controllers to the required 5V HUB75 RGB LED matrix panels. It is designed for 38 pin ESP32 development boards, Raspberry Pi computers, and other 3.3V microcontrollers used in programmable LED matrix projects.

Onboard 74HCT245 buffer and line-driver ICs perform 3.3V to 5V level shifting across all 13 HUB75 signal lines. This buffered level translation produces cleaner digital signals than directly connecting a 3.3V controller to a 5V matrix panel, helping eliminate ghosting, dim pixels, and other display artifacts.

ESP32 HUB75 Adapter with V2.x GPIO Mapping

This ESP32 HUB75 adapter is designed to seat a classic 38-pin ESP32-DevKitC style module. It provides a complete GPIO-to-HUB75 interface using the board's V2.x pin mapping, simplifying wiring for LED matrix displays, scrolling signs, dashboards, animations, and interactive projects.

Firmware pin definitions must match the board revision. Earlier V1.x versions use a different GPIO mapping. This Rev 2.2 adapter uses the V2.x mapping and must be configured accordingly in the selected HUB75 driver library.

HUB75 Level Shifter for 3.3V Controllers

Standard HUB75 LED matrix panels typically expect 5V logic signals, while ESP32, Raspberry Pi, and many modern microcontrollers output 3.3V logic. A direct connection may work inconsistently or produce ghosting and dim-pixel artifacts. This HUB75 level shifter uses 74HCT245 devices to buffer and translate the control signals to reliable 5V logic levels.

The board can also serve as a Raspberry Pi HUB75 adapter or a buffered interface for other compatible 3.3V logic platforms. Raspberry Pi and general microcontroller installations require appropriate external wiring based on the documented V2.x GPIO-to-HUB75 pinout.

RGB LED Matrix Power Requirements

The connected HUB75 RGB LED matrix panel must be powered by its own dedicated 5V power supply. The panel power ground and adapter board ground must be tied together to establish the common ground reference required for reliable signal operation.

The adapter is intended for signal interfacing and level translation. It does not replace the high-current 5V supply required by an RGB LED matrix panel.

HUB75 Firmware and Panel Configuration

The RGB LED matrix adapter works with common HUB75 driver libraries for ESP32, Raspberry Pi, and other supported controllers. Firmware settings vary by panel type, scan configuration, and driver IC.

For FM6126A-based matrix panels, a typical starting configuration includes:

• Enable the FM6126A panel driver
• Set clock phase, or clkphase, to false
• Use a minimum refresh rate of approximately 150 Hz for clean output
• Select the Rev 2.2 V2.x GPIO mapping

A product reference manual and setup wiki are available for detailed pinouts, wiring information, and configuration guidance.

HUB75 Adapter Board Applications

• ESP32-driven RGB LED matrix displays (Requires 38 Pin ESP32 For plug and play)
• Raspberry Pi LED matrix projects
• Scrolling text and animated message signs at high FPS
• Real-time dashboards and status displays
• Interactive lighting and digital art installations
• Maker electronics and microcontroller projects
• Reducing ghosting and dim-pixel artifacts on HUB75 panels

RGB Matrix Adapter Board Specifications