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

I recommend version 2.3.0 of the esp8266 board libraries. With 2.4.0 I experienced unstable receivement of packets.

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.

Cahnge log GGS67

• Set dummy aray length of 1 to additional_info[] in data union of __cemi_msg because th enew compiler does not allow for flexible arrays in unions
• Made ROOT_PREFIX for web server permanent which allows /knx prefix to be used with common web server without having to edit the library
• Added withPrefix argument to start() methid, defauletd to false so that it is compatible with previous use withouzt overriding ROOT_PREFIX. Set withPrefix to true to use the prefix
• Introduced KNX_WEB_PATH macro to automatically select the literal string path with or without prefix at runtime
• Introducef F_KNX_WEB_PATH to accomodate the F(s) which is used for strings that should be stored in program space (flash) rather than loaded into RAM at program start. Note that in this library WString.h is used which actually loads the string into memory, but still there will be only one copy instead of 2