ESP8266 Community Forum

- Sun Jan 18, 2015 9:03 am #7614 Do you get anything in serial console on 'failed bootup'?

- Sun Jan 18, 2015 9:46 am #7617

Hey,

Can you guys help me? I have the same problem but on a different config.

1) I also have a 5V 2A max main power supply (or directly to a USB port)
2) my voltage regulator is a LM3940 for which i have a 100uF cap between the 3.3V and GND.
3) CH_PD to 3.3V directly
4) 3.3V connected to a LED through a 1k resistor and then connected to the RX pin. (also tried with this disconnected)
5) TX pin connected to FTDI

I tried pulling up the GPIO0 pin to vcc through a 10k Resistor like you suggested but it still requires a few powers or a reset to boot up.


Should I just use another voltage regulator? Are any other pins that should be pulled (up or down)?

Hi!
Few questions for you:
1) have you tested the voltage between vcc and gnd pins of esp8266? It's 3.3v and stay 3.3v also when the board doesn't boot?
2) what's firmware are you using?
3) have you tried to connect CH_PD to 3.3v through a 10k resistor?
4) are you sure that your power supply (5v 2a) it's not fault?
5) have you tried to leave tx and RX floating and check if you can find the esp8266 WiFi network with your PC or smartphone? You must set AP mode on esp8266 before disconnect the RX and TX

Hey,

Thanks for replying...

1) I have tested it and it's always 3.25 V ( it drops during boot to 3.21V in both cases of boot success )
2) I'm using the 20150107 nodeMCU firmware
3) I tried it now. Same thing happens. Can anyone point me to a boot-up schematic (where I can see all the required pulls for all the pins - is there such a thing?)
4) not 100% sure but I tried with another 2A 5V source and get the same results
5) The board connects automatically and gets it's ip without me doing anything in code - I tried booting it without the rx/tx pins connected (and testing by ping or by connecting to it) and it takes a few boot-ups or a boot and restart for it to work
It sometimes works the first time but as I want to connect it to a 220V SSR ( or EMR) I would like it to connect on first try.


I also get weird characters when it boots (even on successful boots).
The characters I'm getting are more or less the same (some random line finishing almost always in 'BC').
It's always there but on successful boots the next line is the nodeMCU welcome line.

Thanks

- Sun Jan 18, 2015 10:19 am #7618 Umh...it's very strange...

I have THE SAME situation but i was blaming the LM317 voltage regulator... You are using the LM3940 that suit perfect to this module so now i'm afraid that it's not the voltage regulator...

Please if you fix the problem PLEASE share the solution with me, thanks

Maybe others can spot the problem, i can't

- Sun Jan 18, 2015 12:07 pm #7626 Hey all,

My esp now reliably boot up every time.
What I did was retest every component and got the same results.

Lastly I re-flashed to the 20141222 nodeMCU firmware and it now boots up fine (everytime).

So I think it's either the 20150107 nodeMCU firmware or I did something during the flash process to screw it up.


Anyway thanks for the advice....