Detailed Description

SDI-12 sensor-bus command / response codec (DETWS_ENABLE_SDI12).

SDI-12 is the 1200-baud single-wire ASCII bus used by environmental / agricultural sensors (soil moisture, water level, weather). A recorder addresses a sensor by a single character (0-9, A-Z, a-z) and sends <addr><command>!; the sensor replies <addr>...<CR><LF>. This codec builds the standard commands, parses the measurement response (atttn: seconds until ready + value count), splits the data values, and does the SDI-12 CRC (the aMC! / aCC! CRC-protected variants).

The wire is a single 1200-baud 7E1 line with a 5 V break / marking convention; on an ESP32 it needs a small level / direction circuit, and the UART transport is the application's. Pure codec, host-tested. Bridge a sensor string onto Wi-Fi by polling aM! / aD0! and publishing the values.

Author: Douglas Quigg (dstroy0)

Date: 2026

Definition in file sdi12.h.