How to Use HUB75: Examples, Pinouts, and Specs

The HUB75 is a standardized interface widely used for connecting LED displays, particularly in large-scale video walls and digital signage. It provides a simple and efficient way to communicate between a display controller and LED modules. The HUB75 interface is known for its ability to handle high-speed data transmission, making it ideal for applications requiring vibrant, dynamic, and high-resolution visuals.

• Large-scale video walls in stadiums, malls, and public spaces
• Digital signage for advertising and information display
• LED matrix displays for animations, text, and graphics
• Interactive installations and art projects
• Scoreboards and event displays

• Voltage Supply: Typically 5V DC
• Data Protocol: Parallel data transmission
• Supported Colors: RGB (Red, Green, Blue)
• Refresh Rate: Up to 1920Hz (depending on the controller and LED module)
• Connector Type: 16-pin or 20-pin ribbon cable
• Maximum Resolution: Depends on the controller and LED module, commonly 32x16 or 64x32 pixels per panel

The HUB75 interface uses a 16-pin or 20-pin connector to transmit data and control signals. Below is the pinout for a standard 16-pin HUB75 connector:

For 20-pin connectors, additional pins may be used for extended functionality or higher resolutions.

1. Connect the HUB75 Interface: Use a ribbon cable to connect the HUB75 connector on the LED module to the corresponding connector on the controller board.
2. Power the Module: Provide a stable 5V DC power supply to the VCC and GND pins of the HUB75 interface.
3. Send Data: Use a compatible controller (e.g., Arduino, Raspberry Pi, or a dedicated LED controller) to send RGB data and control signals (CLK, LAT, OE, and row address bits).
4. Configure the Controller: Ensure the controller is configured for the correct resolution and refresh rate of the LED module.

• Power Supply: Ensure the power supply can handle the current requirements of the LED module, especially for large displays.
• Signal Integrity: Use short and high-quality ribbon cables to minimize signal degradation.
• Heat Management: Large LED displays can generate significant heat; ensure proper ventilation or cooling.
• Controller Compatibility: Verify that the controller supports the resolution and refresh rate of your LED module.
• Software Libraries: Use libraries like Adafruit GFX or PxMatrix for Arduino to simplify programming.

Below is an example of how to control a HUB75-based LED matrix using an Arduino UNO and the PxMatrix library:

#include <PxMatrix.h>

// Define display size (e.g., 32x16 pixels)
#define DISPLAY_WIDTH 32
#define DISPLAY_HEIGHT 16

// Define pin connections
#define P_LAT 10  // Latch pin
#define P_A  A0   // Row address A
#define P_B  A1   // Row address B
#define P_C  A2   // Row address C
#define P_D  A3   // Row address D
#define P_OE 9    // Output enable pin
#define P_CLK 8   // Clock pin

// Create PxMatrix object
PxMatrix display(DISPLAY_WIDTH, DISPLAY_HEIGHT, P_LAT, P_OE, P_A, P_B, P_C, P_D, P_CLK);

void setup() {
  // Initialize the display
  display.begin(16); // Set brightness (0-255)
  display.setBrightness(100); // Adjust brightness level
}

void loop() {
  // Clear the display
  display.clearDisplay();

  // Draw a red rectangle
  display.fillRect(0, 0, 16, 8, display.color565(255, 0, 0));

  // Draw a green rectangle
  display.fillRect(16, 0, 16, 8, display.color565(0, 255, 0));

  // Draw a blue rectangle
  display.fillRect(0, 8, 16, 8, display.color565(0, 0, 255));

  // Update the display
  display.showBuffer();
  delay(500);
}

• Install the PxMatrix library in the Arduino IDE before running the code.
• Adjust the pin definitions and display size to match your specific setup.

1. No Display Output:

   • Verify all connections, especially the ribbon cable and power supply.
   • Ensure the controller is properly configured for the LED module's resolution.

2. Flickering or Dim Display:

   • Check the power supply for sufficient current output.
   • Reduce the brightness level in the software to avoid overloading the power supply.

3. Incorrect Colors or Patterns:

   • Ensure the data pins (R1, G1, B1, etc.) are correctly connected to the controller.
   • Verify the software configuration matches the LED module's specifications.

4. Partial Display Not Working:

   • Check for loose or damaged connections in the ribbon cable.
   • Test the LED module with a different controller to rule out hardware issues.

• Can I daisy-chain multiple HUB75 panels? Yes, most HUB75 panels support daisy-chaining. Connect the output of one panel to the input of the next, and configure the controller for the combined resolution.

• What is the maximum cable length for HUB75? For reliable operation, keep the ribbon cable length under 50cm. Use signal boosters for longer distances.

• Can I use a 3.3V controller with HUB75? Most HUB75 modules require 5V logic levels. Use level shifters if your controller operates at 3.3V.

By following this documentation, you can effectively integrate and troubleshoot HUB75-based LED displays in your projects.