ESP8266 Community Forum

- Sat Feb 14, 2015 12:17 pm #9757 Using NodeMCU firmware on ESP-01, GIPO2 goes high, low, and then high during power on process (very short, 1 or 2 seconds). If you use the module to control LED, this power on pin state change is minor problem. If you use the module to control garage door, the power on state change is kind of annoying -- your garage door will open or close just because you plug in power.

Is the above a NodeMCU firmware problem or a hardware problem? Do other GPIO pins (say, with ESP-03) not have the above problem? How do you get around? -- adding a switch so that the output doesn't see the state change?

When you wake up the module from deep sleep, won't you have the above problem?

(After the power on process, you can do any magic you like.)

Thank you.

- Sat Feb 14, 2015 1:06 pm #9761

Using NodeMCU firmware on ESP-01, GIPO2 goes high, low, and then high during power on process (very short, 1 or 2 seconds).

GPIO2 is one of the inputs that the chip reads to decide how it is going to boot.

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

I suspect that you are seeing the read cycle with a pulldown as it checks for GPIO2 being held high.

Similarly, changing GPIO0 or GPIO2 before the boot has finished will cause it to boot into different modes and not run Lua.

ESP8266 for dummies, LuaLoader and project updates: http://benlo.com/esp8266

- Tue Feb 17, 2015 4:49 am #9998

If you use the module to control garage door, the power on state change is kind of annoying -- your garage door will open or close just because you plug in power.

You may invert the signal and use logic HIGH as inactive/logic LOW as active signal. For reverting the signal you may use e.g. Normally Closed contacts of relay.

Regards
M.
(First post so - Hi to everybody )