I use this.
https://www.mouser.jp/ProductDetail/Esp ... 2BqWdhIQ==
- antenna impedance matching is not done yet
- the power supply is 3.3V and stable
- ESP8285 sends initial messages when it is powered on.
- Confirm with oscilloscope that message like "AT\r\n" from MCU to ESP8285 is sent, but return message is not sent.
- GPIO0 is not stable and oscillated even though it is pulled up to 3.3v by 12k ohm. 3.3v is stable.
Do I have to install AT command firmware to ESP8285?