Detailed Description

DMX512 framing + RDM (ANSI E1.20) management codec (DETWS_ENABLE_DMX).

DMX512 (lighting / stage control over RS-485) is positional: after a break, a start code octet (0x00 for dimmer data) is followed by up to 512 channel slots, with no checksum or in-frame addressing. This codec assembles / reads that slot array, and implements RDM (Remote Device Management, ANSI E1.20) - the addressed management layer that shares the DMX wire: a real packet with 48-bit source / destination UIDs, a command class + parameter id, and a 16-bit additive checksum.

The break + RS-485 direction are the application's (a MAX485-class transceiver on a UART at 250 kbit/s, 8N2). This is the byte-level framing layer. Pure and host-tested. Bridge a lighting rig onto Wi-Fi: drive DMX slots or discover / configure RDM fixtures from the web.

Author: Douglas Quigg (dstroy0)

Date: 2026

Definition in file dmx.h.