ESP8266 Community Forum

- Tue Jan 19, 2016 11:12 am #39236 Hello, I'm struggling with bringing the nodemcu dev board up from a deep sleep (coding in C++ arduino framework). The board RTC timer correctly triggers the wake up, but the esp12 continuously flashes the led (slower than rx/tx) and spits garbage on the serial (neither 74880, nor 115200, nor 9600 work, still garbage).

I have to manually break (or put in a button) the D0/GPIO16 to RST ping jumper.

Another observation - if I connect GPIO16 and RST out of the box, it doesn't start and stays in this same mode on initial boot, until I break the link and let it boot up.

I've read about a need to pull up GPIO0 and GPIO2 with 4.7K resistors to a VCC line, as well as a mention of 10-15K pull up resistor for the GPIO-RST, although it didn't seem to help in my case.

I admit I could have easily messed up something, I'm definitely a newbie to the hardware scene

It looks like if I resolve the problem of esp12 getting stuck on initial boot my wake up problems will get solved too. The symptoms are the same: it spits garbage out on serial, flashes the led at a medium speed and won't proceed until I break GPIO-RST link (even without any resistors).

Please help

- Tue Jan 19, 2016 11:29 am #39240 Have you just simply tried disconnecting everything from all the other pins (yes, all your resistors and all) and simply wiring GPIO16 to RST? The board should work fine and it should similarly wake up from deep-sleep -- I have a Nodemcu 1.0 - devkit and it works for me. If it doesn't work like that then there's something wrong with the devkit you're using.

- Tue Jan 19, 2016 12:13 pm #39242 Yes, I have wired GPIO16 and RST directly only to get same results. Dunno, maybe it has to do with the other i2c components, but they're on the other pins anyway.

I've tried 3 boards already, but thanks for sharing.

- Tue Jan 19, 2016 12:19 pm #39243

Yes, I have wired GPIO16 and RST directly only to get same results. Dunno, maybe it has to do with the other i2c components, but they're on the other pins anyway.

But I asked if it works if you remove all the other things you've connected to other pins. If it does then the issue lies with the other pins you have in use.