ESP8266 Community Forum

- Sat Nov 03, 2018 3:28 am #79002 Hi, thanks for answer.
Electrically its really fine. I would suspect that I am not in the proper boot mode or something. I have additionally grounded the GPIO15 and tied the GPIO2 and GPIO0 to VCC, but that did not help...

http://www.przenioslo.com

- Sat Nov 03, 2018 8:22 am #79003 Do not ground GPIO15. It needs to be low at a point in startup but it also can, and does, get changed to an output at some points and produces a high. Use only resistors for pull up and down.

I will typically connect a status led to GPIO15, in addition to the 10K pull down.

GPIO2 normally has connected the on module blue status led. It is used as status and also as the pull up for that pin. An led (with series resistor) is not a proper pull up in my opinion (due to the voltage drop by the led) but it does seem to work for this processor. I still use a single resistor to Vcc on any of my designs.

GPIO0 also needs a pull up. I use 10K for all the pull ups, down.

Take a look at this page for an explanation on the GPIO behaviours.
https://www.mjt.me.uk/posts/esp8266-gpi ... and-reset/

- Sat Nov 03, 2018 8:40 am #79004 Hello, thank you for answer.
I only had some parts lying around at home, so I pulled down GPIO15 through a 3k9 resistor and tied (directly) GPIO0 and GPIO2 to VCC. At monday I will be able to replace the hard ties to VCC with 10k pull-ups. But is this really the case here since the device boots up but just behaves weirdly (Echo instead of AT commands responses)?

http://www.przenioslo.com

- Sun Nov 04, 2018 1:57 am #79011 Hello,
I have managed to solve the problem thanks to this topic: https://electronics.stackexchange.com/q ... nds#161330
I had to turn on CR+LF when I press return. This makes sense. Now everything works. Thank you for the answers.

http://www.przenioslo.com