ESP8266 Community Forum

- Mon Feb 05, 2018 12:06 pm #73722 Hello,

I have a simple electronic circuit with ESP12E (esp8266) wifi module, PIC18F27K40, RFM95W Lora module and LM317 (for power-up 3.3 V output).

I have a very bizarre situation :

- version 1 of the PIC18F program :
- ESP12E works fine when connecting my pcb Gnd to the Gnd pin of the PicKit3 cable (no power-up from PC) + AC adaptor for input power of the LM317
- ESP12E works fine when using only AC adaptor for input power of the LM317

- version 2 of the PIC18F program (same PIC, pins and interrupt configs) :
- ESP12E works fine when connecting my pcb Gnd to the Gnd pin of the PicKit3 cable (no power-up from PC) + AC adaptor for input power of the LM317
- ESP12E does not work (no uart communication between ESP12E and PIC18F) when using only AC adaptor for input power of the LM317

- version 3 of the PIC18F program (same PIC, pins and interrupt configs) :
- ESP12E does not work when connecting my pcb Gnd to the Gnd pin of the PicKit3 cable (no power-up from PC) + AC adaptor for input power of the LM317
- ESP12E does not work when using only AC adaptor for input power of the LM317

Does anyone has any clue why the ESP12E uart communication is failling ?
Thank you.

- Thu Feb 08, 2018 1:52 am #73792 try disconnecting esp rx pin during power up.