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ER: Configure LED block: FAST Serial Protocol Reference, EXP Port

This command was added in firmware version 0.10

This feature is not yet released

This documentation is for a feature that is not yet released. Details and features may change.

The ER: command is used to configure an LED block which is a group of LEDs that can be controlled together via single FAST serial command or an EXP show script. Each block has a number (0-F, which is 0-15 but they're in hex) and then one or more LEDs (up to 32).

The order of the LEDs in this command will be the logical order of the LEDs when a show targeting this block is run. Note that this does NOT have to be the same order as the physical order of the LEDs in the chain in your machine. This means you can wire your LEDs in whatever way makes sense, and then define the logical blocks separately as they make sense.

You can also target these LED blocks with the regular RD: and RS: commands which use LED indexes. See those commands for more information.

Command syntax

ER:<block>,<type>,<led1, led2,...ledN><CR>


The number of the block you want to configure, in hex. Valid block numbers are 0-F (0-15). Blocks 0-3 are reserved and correspond to the physical LED hardware ports on the breakout board and cannot be reassigned. Blocks 4-F (4-15) are user blocks and are available for custom configuration.


Sets the type of LEDs in the block. (WS2812 RGB, SK6812, APA102, etc.) This features is not yet implemented. Just use 0 for now.

<led1, led2,...ledN>

A comma-separated list of one or more LED index IDs (in hex) for the LEDs that will be part of that block. A single block of LEDs can span multiple physical ports. You can configure up to 32 LEDs in a block.


  • ER:P means the port assignment was successful.
  • ER:F means the port assignment failed.


Define Block 4 to include LEDs 0-3:


Define Block 5 to include just the even LEDs from the first port:


Define Block 6 to include the first 4 LEDs from the first port, and the first 2 LEDs from the third port (remember LED indexes are hex, so LEDs 64 and 65 are LEDs 40 and 41)):


Define Block 7 to include four LEDs that are not in physical sequence, but that will be logically in sequence:


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