Summary

LPC is a P10 module driver using HUB75 protocol and controlled by standard DMX interface. It embeds a micro-SD card for storing data to display.

See attached datasheet for complete description.

Hardware design

Block diagram

Below is the functional block diagram of the board.

Power supply

The LED Panel Controller HW1.0 operates at +3.3 V provided by an LDO voltage regulator. A red LED connected to the output of the LDO confirms the board is well powered. The board doesn’t supply power to the panels because of the high current drain required. It only provides the control signals through the HUB75 connectors and panels should be externally powered.

Several resistors allow the user to connect or not the different grounds of the board: the main ground plane, the DMX ground, the DMX cable shielding and the casing of the micro–SD connector.

MCU and programming interfaces

The LED Panel Controller HW1.0 is based on an STM32 microcontroller developped by STMicroelectronics: the STM32F405RGT6 in LQFP–64 package. It is clocked by a 16.369 MHz TCXO to ensure DMX baud-rate accuracy in a wide range of temperature.

Two interfaces can be used to program the MCU and debug the embedded software: either the SWD interface or the complete JTAG interface.

Communication

The board communicates with external applications through a bi-directional UART. This serial link can be connected to several interfaces: a DMX network via an RS485 transceiver (including a 120R terminator), an USB cable through a UART–USB converter or an FTDI cable directly.

In most of applications, the LED Panel Controller will act as a slave: the MCU will receive commands from a host and will execute them to diplay a given picture.

Micro–SD card

The boards includes a micro–SD card connector allowing the user to embed more memory space. The micro–SD card is connected to the MCU through a 4–wires SPI connection. This hardware feature is usefull for display applications which require lot of memory to store pictures or videos.

LED panels

The board is capable of driving two independent P10 modules or more by using a series association on a single port. Those LED panels use a standard interface called HUB75.

Embedded software

The software embedded in the STM32 MCU was developed under Eclipse IDE and AC6 System Workbench plugin. The source code is available on GitHub @ https://github.com/dad55/LED_Panel