ESP8266 Community Forum

- Mon May 16, 2016 11:42 pm #47540 I am using an ESP8266-12E module (from an eBay supplier) and I can successfully program it in the arduino IDE and can communicate via WiFi to another device.

However, after powering it down and reconnecting to the power source (2 off new 1.5V series connected batteries giving about 3.2V) I lose the WiFi connection. I of course, remove the connection between ground and GP100 and GP1015 before powering up again.

Is it possible that the EPROM in the ESP8266-12E module is faulty and cannot retain what is in memory?

I have to reprogram the ESP8266-12E to get it operational again.

Has anyone else experienced this problem?

- Tue May 17, 2016 1:24 am #47547 Hi, GPIO 15 needs to stay connected to Ground.

ESP-------------Flash-------------Normal
GPIO O--------GND--------------Vcc via 10K******the only change******
GPIO 2---------Vcc via 10K-----Vcc via 10K
GPIO 15-------GND--------------GND
RST-------------Vcc----------------Vcc
CH_PD (EN)--Vcc----------------Vcc

- Wed May 18, 2016 7:20 am #47597 Thanks Barnabybear,

Your connection suggestion fixed it. I got the information from the following site:
http://www.agcross.com/2015/09/the-esp8 ... -firmware/
This shows a circuit with GP10 0 and GP10 15 connected together and then via a switch to GND. Just connecting GP10 15 permanently to GND and connecting GP10 0 to GND only during uploading did the trick.
This caused me hours of frustration having the incorrect connection.

Although this is OK now, I wonder if there is a good explanation somewhere of the pin functions (maybe there is in Chinese).

- Wed May 18, 2016 8:40 am #47599 Well known page here :

https://github.com/esp8266/esp8266-wiki ... ot-Process