ESP8266 Community Forum

- Sat Dec 02, 2017 8:42 pm #72257 Actually, I semi have an idea... GPIO2 and 15 are tied to rotary encoders via the RJ45 jack. So when connected there's a chance that they're pulled up/down appropriately. Oddly though, it would sometimes boot up just fine when no encoders were connected.

Anyways, I've manually tied GPIO 15/2 down/up and removed the level shifter since apparently Espressif on Facebook says all the GPIO pins will handle 5V just fine. Anyone mind taking a quick look and make sure I didn't make any other mistakes? I've switched to using GPIO12/14 which per the docs also support external interrupts and hence should work fine with the Encoder library in an effort to make booting more reliable.

https://synfin.net/misc/espdsc2.pdf

Thanks

- Sun Dec 03, 2017 4:49 am #72264 GPIO02 would have worked OK as these pins have a weak internal pull-up (~36K) so by default they are high if not connected. GPIO15 needing to be low definitely needs the pull down and low enough to overcome the internal pull up.

There have been different opinions on how far to trust the 5V handling. I would have included series resistors to be on the safe side.

- Sun Dec 03, 2017 11:34 am #72272 The encoders are putting out 5mA and looks like the diodes on the 8266 GPIO pins can take 20mA. Should be ok without the current limiting resistor, but I suppose adding them in like you suggest would add some protection.

Thanks for the advice!