FAQ: Collection of links and information about RGB LED Panels and FPGA

led_panel.md

A common name for the interface is HUB75

The displays use shift registers for columns and two sets of row multiplexers.

Typical organization

32x32 panel

• Organized in two halfs of 16x32 tiles
• 32 bit long RGB column drive shift registers
• 4 bit to 16 row drive demultiplexers

64x64 panel

• Organized in two halfs of 32x64 tiles
• 64 bit long RGB column drive shift registers
• 5 bit to 32 row drive demultiplexers

LED Panel Hardware

You can find the collection of the datasheets of the parts used inside the panels in kbob's repository

The list of the most important chips found on a panel is the following:

• 16Bit Shift register with current control open-drain outputs
  • ChipOne ICN2047 or
  • TI TLC5926 or
  • TI TLC5927
• n to 2^n line driver decoder/demultiplexer
  • ChipOn ICN2012 or
  • 74HC138 or
  • 74HCT138

For more datasheets and reverse engineered schematics for several LED Panel types/designs refer to esden's led panel docs GitHub repository.

FPGA Drive hardware

We are using the iCEBreaker FPGA development board and a LED panel driver PMOD.

Both devices will be available soon on Crowd Supply iCEBreaker FPGA dev board crowd funding campaign. Definitely subscribe to get notified as soon as the iCEBreaker campaign launches.

Streams

• Scanlime icestudio LED Panel design for iCEBreaker
  • Episode 1
  • Episode 2
  • Episode 3
  • Episode 4
  • Episode 5 -> in progress

FPGA Design

• Scanlime Code is published on GitHub
• Bob Miller's icebreaker candy on GitHub
• tnt's ice40-playground/projects/rgb-panel on GitHub

Articles

• Sparkfun Blog Article by Nick Poole
• RGB LED Panel Driver Tutorial - by Glen Akins
• Adafruit guide for Arduino

Video

• In detail video by Mike Harisson aka. mikeselectricstuff
• Outdoor LED Screen teardown (+how to drive LEDs with video) by Mike Harisson aka. mikeselectricstuff

Contributing

Please feel free to provide additional entries to this collection. :D You can find me and many others on gitter in:

• Scanlime Live channel
• 1BitSquared Discord Server, #icebreaker and #led-cubism channels

It would be good to add a section on hardware hacking. Here's what I know of.

The WS2812 ear requires two 10K resistors in 0603 packages and a BSS138 MOSFET in SOT23 package. And a header.

The RGB LED pad fits a Cree CLX6F LED.

You can piggyback a QSPI RAM chip onto the flash chip and bring the CS pin out to the nearby pad. The suggested part is Lyontek LY68L6400. It is available from lcsc.com. The datasheet is here. http://esp32.de/lyontek/pSRAM/LY68L6400_0.3.pdf