EVOFW3 Autotune

NOTE: this procedure is only intended for devices like thos described below. It is not necessary for any device bought from Indalo Tech

Some CC1101 modules, especially the green ones have 26MHz crystals that are so inaccurate that the standard configuration parameters for the cc1101 are not capable of tuning the cc1101 to the required 868.3MHz carrier frequency resulting in very poor ability to both receive and transmit evohome messages.

The evofw3 firmware has an autotune mechanism to overcome this problem. This will try to find the optimum frequency parameters for your cc1101.

In order to autotune a module connect it to a host computer and open a basic serial connection. For simplicity of use the tool used should either have local echo enabled or have an input line window that can be used to type commands. The tool should be configured to send both CR and LF at the end of each line.

To start the autotune process enter the command !FT

The autotune process takes approximately 45 minutes. While it is running You will see good AND bad received messages reported in the serial together with lines that look like !C D 21 65 5A

You can check whether it's complete at any time by sending !F

You can re-run the autotune process at any time without resetting the calibration. You should not expect exactly the same result every time. A small difference should produce a module that is accurate enough to transmit and receive messages successfully.

You can reset the tuning parameters to default with !FR followed by !FS

It will report the current frequency parameter and, if it's still searching, will report Tuning

When it has finished you can save the tuning parameters with !FS