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DMX

From Trammell Hudson's Projects

DMX512

Geometric lamp, realized

WS2822S RGB LEDs will have DMX512 control, so we'll need to update LEDscape to support them. The new boards already have RJ45 connectors with RS485 signalling, allowing us to directly interface with commercial DMX devices; the WS2822S will still need an interface board to receive the differential signals and translate them to single ended +5V logic.

Annotated trace of DMX-512 signal.png The maximum update rate is a bit slower than the WS2812 800 KHz protocol -- 250 Kbps is normal, 750 Kbps is the max for DMX512. Each output from the LEDscape board can drive up to 512 devices, but since each RGB is three channels there is a max of 170 WS2822S LEDs per output.

TODO: Are terminators required? How do we handle assigning addresses easily in the field?