Not Receiving data 'No ACK from S1 for xx query'

[serimi89]

Hey and thanks a lot for your effort in making this available via ESPHome.

I am running into errors with regards to the UART comms, but that could possibly related to my hardware config. Just wanted to run this past you to see if it is a software issue.

The error im getting is:

[13:53:48][W][daikin_s21:265]: No ACK from S21 for F1 query
[13:53:48][W][daikin_s21:265]: No ACK from S21 for F5 query
[13:53:48][W][daikin_s21:265]: No ACK from S21 for RH query
[13:53:48][W][daikin_s21:265]: No ACK from S21 for RI query
[13:53:48][W][daikin_s21:265]: No ACK from S21 for Ra query
[13:53:48][W][daikin_s21:265]: No ACK from S21 for RL query
[13:53:48][W][daikin_s21:265]: No ACK from S21 for Rd query

My hardware is a regular ESP32 module (not a faikin) that I have connected only to RX and TX of the AC unit. I have tried using a level shifter on the RX/TX to bring the output down from 5V to 3.3V but there is no difference in the output. Any clues?

[asund]

You should also connect ground as a reference for the signals. May be able to get it to work without it, but why gamble?

My pin configuration:

    tx_pin:
      number: GPIO43
      mode:
        output: true
        open_drain: true  # daikin pulls up to 5V internally
    rx_pin: GPIO44

The ESP IO pins are heavily implied to be 5V tolerant, but documentation is weirdly not up front about it. Using open drain for my TX pin pulls it down from 5V to ground without need for a level shifter.