u/EastyUK

Incase anyone is hitting the scenaro with the same issue, hopefully save someone my spin of frustration. 😄

Symptoms:

• ENS160 boots successfully, firmware version reads correctly
• I2C scan finds device at correct address
• Stuck permanently in ENS160 readings unavailable - Normal Operation but readings not ready
• Never produces eCO2, TVOC or AQI readings regardless of how long it runs

Hardware:

• ESP32-C6 running ESPHome esp-idf framework
• ENS160+AHT21 combo breakout board
• Multiple I2C devices on same bus (AHT21 at 0x38, ADS1115 at 0x48, ENS160 at 0x52)

What didn't work:

• Waiting 5+ days powered continuously
• Adding 30s boot delay
• Removing compensation block
• Dropping I2C frequency to 10kHz (actually made it worse)

What fixed it: Increasing I2C frequency to 800kHz

yaml

i2c:
  sda: GPIO6
  scl: GPIO7
  scan: 
true
  frequency: 800khz

The ENS160 apparently needs a fast enough I2C clock to complete its internal initialisation handshake. At low frequencies it communicates but never exits warmup state.