ESP8266 Community Forum

- Fri Jan 30, 2015 6:43 pm #8549

Connect the GPIO hard to VCC is the best way to hell. Search error elsewhere.

Why you say that?
After doing that i got 100% boots and 0% restart...
If i pull-up with 1Komh i get 70% boots and a few restarts

EDIT:
i found there (https://github.com/esp8266/esp8266-wiki ... e_versions) that GPIO0 "Has internal pull-up"
So...can you please point me to where you found this information?

- Sat Jan 31, 2015 4:27 am #8576 It is unacceptable to connect universal inputs/outputs directly to the power supply or ground.
Connect GPIO0, GPIO2, RESET (CH_PD may be also) to Vcc through separate resistors around 5k6. Buttons to the ground on GPIO should have a series resistor around 330 ohm. If that fails, then you're doing wrong otherwise or can be yours circuits already damaged.

So...can you please point me to where you found this information?

My experience with microcontrollers.

- Sat Jan 31, 2015 5:26 am #8584

It is unacceptable to connect universal inputs/outputs directly to the power supply or ground.
Connect GPIO0, GPIO2, RESET (CH_PD may be also) to Vcc through separate resistors around 5k6. Buttons to the ground on GPIO should have a series resistor around 330 ohm. If that fails, then you're doing wrong otherwise or can be yours circuits already damaged.

So...can you please point me to where you found this information?

My experience with microcontrollers.

Thanks for your reply.

Today I tried with some resistors... the max resistor I can put on GPIO0 without get a lot of failed boot is 220omh. I tried with 476omh (NOT KOMH!) and i got a lot of failed boots.

I tried 3 boards...I don't think that they are all damaged...

What do you think about internal pullup of GPIO0?

EDIT:
maybe a found the problem! The pullup resistor on RESET pin must be greater than the pullup resistor on CH_PD and GPIO0! Now i'm testing this setup:
RESET: 65Komh
CH_PD: 10Komh
GPIO0: 10Komh
and i didn't got a failure yet...i will update you soon!

- Sat Jan 31, 2015 6:31 am #8589 And where is GPIO2? It is also suitable to treat. It is very important. But the value of resistance are not importance. Internal pullup is good, but the external one is assurance.

The drop voltage on your stabilizer LM317 is almost 2V. Your power supply 5 volts has not a large margin for function properly.