How to set up HA to read and set an MQTT topic from/to FHEM?

1

Hello!

I receive MQTT messages in HA from an FHEM instance, among them lots of parameters and values form my heating.

One of the topics is: fhem/Mythz/p07FanStageDay
It can have a value of 0, 1, 2, or 3.

I would like to a) read its value in HA and b) also set its value in HA, i.e. for the latter, I would have to publish some kind of set topic from HA back to FHEM (I assume).

So far, I am only able to read simple values in HA from FHEM, such as:

mqtt:
  sensor:
    - name: Mythz_outsideTemp
      state_topic: "fhem/Mythz/outsideTemp"

I.e. this already works.

However, I have no idea how to read and especially set this fhem/Mythz/p07FanStageDay. Can somebody please provide me with a hint into the right direction? Thank you so much! :heart: