Cloned from supersjimmie which cloned from Klusjesman,
Complete rework of the itho packet section, cleanup and easier to understand, improved stability
* Library structure is preserved, should be a drop in replacement (apart from device id)
* Decode incoming messages to direct usable decimals without further bit-shifting
* DeviceID is now 3 bytes long and can be set during runtime
* Counter2 is now the decimal sum of all bytes in decoded form from deviceType up to the last byte before counter2 subtracted from zero.
* Encode outgoing messages in itho compatible format
* Added ICACHE_RAM_ATTR to 'void ITHOcheck()' for ESP8266/ESP32 compatibility
* Trigger on the falling edge and simplified ISR routine for more robust packet handling
* Move SYNC word from 171,170 further down the message to 179,42,163,42 to filter out more non-itho messages in CC1101 hardware
* Support for RFT-CO2 and RFT-RV devices (monitor values and commands)
Tested on ESP8266 & ESP32, compiles on Arduino Uno but might be memory heavy
Will work with a 868MHz CC1101 module. The CC1150 may also work, except for receiving (which is not required for controlling an Itho EcoFan). A 433MHz CC1101/CC1150 might also work, because it has the same chip. But a 433MHz CC11xx board has a different RF filter, causing a lot less transmission power (and reception).
Connections between the CC1101 and the ESP8266 or Arduino:
CC11xx pins ESP pins Arduino pins Description
* 1 - VCC VCC VCC 3v3
* 2 - GND GND GND Ground
* 3 - MOSI 13=D7 Pin 11 Data input to CC11xx
* 4 - SCK 14=D5 Pin 13 Clock pin
* 5 - MISO/GDO1 12=D6 Pin 12 Data output from CC11xx / serial clock from CC11xx
* 6 - GDO2 04=D2 Pin 2 Programmable output
* 7 - GDO0 ? Pin ? Programmable output
* 8 - CSN 15=D8 Pin 10 Chip select / (SPI_SS)
Note that CC11xx pin GDO0 is not used.
Also note that the GDO2 pin connected to pin 2 on an Arduino. Change #define ITHO_IRQ_PIN in the example ino accordingly.
You should keep the wires to the CC11xx module as short as possible.
Beware that the CC11xx modules are 3.3V (3.6V max) on all pins! This won't be a problem with an ESP8266, but for Arduino you either need to use a 3.3V Arduino or use levelshifters and a separate 3.3V power source.
For use with an ESP8266, you will need the ESP8266 core for Arduino from https://github.com/esp8266/Arduino
For SPI, pins 12-15 (aka D5-D8) are used. A larger ESP8266 model like (but not only) the ESP-03, ESP-07, ESP-12(D, E) or a NodeMCU board is required.