[NASA] Help understand packet sending about esphome_samsung_ac HOT 2 CLOSED

Hi @betaphi, yes your are right. The entire communication of NASA is based on messages. All units receive that messages and the ones with the desired destination address reacts to that massage. There are some generic addresses like Broadcast etc. Also that entire protocol is pretty generic. Its basically there to interchange variables (MessageNumber its Value).

Currently I have impl a very simple way of sending the messages. I put them in a queue and send them on the receiving thread when there is no more data available. This should reduce collections but costs some time (when there are a lot data available).

Inside the S-NET code there is a way of handling this. Each message have a packetNumber. That is basically and Integer witch is incremented for each messages that is getting sent.
In example when you change the target temperature you the a message of DataType::Request. Then other side generates a message of data type DataType::Response with the same packetNumber. So basically it should be possible to send a request, wait and check if the reponse comes and if not, resend the request.

I saw code inside the S-NET code but I did not tried it myself yet. I dont now if every request gets a response etc.

Also I noticed that between the messages there are something like filler bytes. The S-NET code calls them permeable, but I have no clue why they are there.

from esphome_samsung_ac.

Hello @lanwin, thank you for your response.

The interesting thing about the EHS ASHP is that while I (and others) have recorded the NASA-Stream, it never sends messages with other destinations than just broadcast. I find that pretty notable. Maybe you see different results with the air conditioners.

The preamble you mentioned (and I have noticed also) could in fact be a measure in order to combat collisions given that there is no clear master - slave pattern with NASA.

from esphome_samsung_ac.