ESP8266 Community Forum

- Mon Aug 01, 2016 1:40 pm #51896 Thanks all for the ideas. To clarify, the ESP is powered by a dedicated power supply (not the FTDI).
However, as schufti mentioned, the voltage divider does not work the other way around - stupid me . Because I read that all GPIO has over-voltage protection, I "took chances" and cut off both second resistors from TX and RX, respectively.
And it does work now. I'm using the espressif FLASH_DOWNLOAD_TOOLS_V3.3.4_Win and flash the bin that I created with Arduino IDE to 0x0. Why the Arduino IDE is not able to do that directly, I have no idea.
Although the ESP-01 can be flashed and run with the self-made board, the blue LED is still always on. A little dimmer but always on. Interestingly, I can switch it off with

Code: Select allSerial.end();
pinMode(PIN_TX,OUTPUT);
digitalWrite(PIN_TX, HIGH);

Don't forget pullups (typ. 10k) on gpio0, gpio2, rst and EN

Well, I don't have any, yet. However, my 5 ESP-01 are running fine. I'll add these on the next breakout board.

Thx & best

- Mon Aug 01, 2016 4:10 pm #51905 The blue LED is on TX line on almost modules, so if it is glowing, that means you probably a tons of characters sent to TX, usually a stacktrace produced by a crash and repeating all the time because of watchdog resets. The fact you have uploaded a sketch switching TX as a GPIO is only hidding the problem.

Those multiple crashes are generally a symptom of bad power supply.

Can you describe your power source ?
Do you have good 3.3V regulator ?
Do you have big capacitor nearby the ESP, something like 47uF or even bigger.

- Tue Aug 02, 2016 3:06 am #51937 Thanks for the feedback!
I was thinking about any unwanted Serial/TX communication but discarded that thought because the other modules (with the exact same sketch) and the same module (attached on a different board) do not have the always on LED. And a stack trace would mean the module crashed, right? But it did not restart and is responding fine, e.g. answers http requests.
Therefor, I thought about a "physical short" that keeps the LED on.

I used a 1.2A 5V dedicated USB power supply with a LD1117AV33. I also tried my usual setup, 2 AA eneloop (2.8V). And I've tried a 470µF capacitor close to the ESP-01 but the blue LED is not affected in both cases.

Thx & best!

- Tue Aug 02, 2016 7:24 am #51945 Do you means that the same module moved to another breakout board works fine ?
What kind of breakout board is it ?

Then, you're right, it is probably that TX is shorted on this specific board.