Tasmota/lib/esp-knx-ip-async-udp

ESP-KNX-IP

This is a library for the ESP8266 to enable KNXnet/IP communication. It uses UDP multicast on 224.0.23.12:3671. It is intended to be used with the Arduino platform for the ESP8266.

Prerequisities / Dependencies

• You need version 2.4.0 of the esp8266 board libraries.
  • I only tested with lwip v1.4. v2 might work, you need to test yourself.
• You need the ESPAsyncUDP library.
• You need a KNXnet/IP router. A gateway will not work. Alternatively use knxd.

Caveats

Receiving packets should work immediately.

Sending sometimes only works after a substantial amount of time (max 5 minutes in my experiments). In my case, this was fixed by disabling IGMP snooping on the switch(es).

How to use

The library is under development. API may change multiple times in the future.

API documentation is available here

A simple example:

#include <esp-knx-ip.h>

const char* ssid = "my-ssid";  //  your network SSID (name)
const char* pass = "my-pw";    // your network password

config_id_t my_GA;
config_id_t param_id;

int8_t some_var = 0;

void setup()
{
	// Register a callback that is called when a configurable group address is receiving a telegram
	knx.register_callback("Set/Get callback", my_callback);
	knx.register_callback("Write callback", my_other_callback);

	int default_val = 21;
	param_id = knx.config_register_int("My Parameter", default_val);

	// Register a configurable group address for sending out answers
	my_GA = knx.config_register_ga("Answer GA");

	knx.load(); // Try to load a config from EEPROM

	WiFi.begin(ssid, pass);
	while (WiFi.status() != WL_CONNECTED) {
		delay(500);
	}

	knx.start(); // Start everything. Must be called after WiFi connection has been established
}

void loop()
{
	knx.loop();
}


void my_callback(message_t const &msg, void *arg)
{
	switch (msg.ct)
	{
	case KNX_CT_WRITE:
		// Save received data
		some_var = knx.data_to_1byte_int(msg.data);
		break;
	case KNX_CT_READ:
		// Answer with saved data
		knx.answer1ByteInt(msg.received_on, some_var);
		break;
	}
}

void my_other_callback(message_t const &msg, void *arg)
{
	switch (msg.ct)
	{
	case KNX_CT_WRITE:
		// Write an answer somewhere else
		int value = knx.config_get_int(param_id);
		address_t ga = knx.config_get_ga(my_GA);
		knx.answer1ByteInt(ga, (int8_t)value);
		break;
	}
}

How to configure (buildtime)

Open the esp-knx-ip.h and take a look at the config options at the top inside the block marked CONFIG

How to configure (runtime)

Simply visit the IP of your ESP with a webbrowser. You can configure the following:

• KNX physical address
• Which group address should trigger which callback
• Which group address are to be used by the program (e.g. for status replies)

The configuration is dynamically generated from the code.