Welcome. The topic is about this version of the mod . . There is practically nothing in the program and it constantly resets itself. As I do not attach the WiFi support the module itself when blinking the diode works. Is the module defective or am I doing something wrong? .

In the board settings, change Erase Flash to All Flash Contents and reload the programme.

Power supply all correct? I.e. you're probably powering from USB anyway, but you could check that the voltages are correct after the stabiliser etc. Exception indicates a problem with program execution, if it is caused by WiFi code then maybe try clearing memory and uploading new firmware. rst cause 2 it looks like the reset button was pressed. Don't do so many delays because if you start to complicate the code, it will start to watchdog reset the board (rst cause 4). You can give yield() in the main program loop.

I fed 3.3V from the power supply behind the stabiliser and still the same. The button is working, when I hold it down the ESP does not start. I added a delay so that ESP resets more slowly.

Delay in esp does not exist Code: C#Log in, to see the code .

@dasej Install a plug-in for the Arduino IDE called ESP8266/ESP32 Exception Stack Trace Decoder . You will then know specifically where the program is crashing. Otherwise, it's a search in the dark. Link . . Really? Code from Arduino Core for ESP8266 below. It is certainly less blocky than what you presented in your post.Code: C / C++Log in, to see the code Added after 4 [minutes]: . Nonsense. The delay() function in the ESP8266 does not block the execution of other threads or the operation of the WTD.

Well I also have from Arduino CORE for ESP8266.... And my general issue is that the delay doesn't block, but flips to other threads Wifi support etc in this WDT.... Sometimes even advisable to use delay in esp....

@khoam . I received something like this back. Code: IniLog in, to see the code . Added after 1 [minute]: @Jarzabek666 . My dear reader, we are not writing here about DELAY.

@khoam Many thanks works. Two words of explanation.

Okay I actually got something mixed up, although I try to avoid delays anyway, maybe that's what got me worked up. Although I'll admit honestly that I haven't figured out the basics like delay in the source files. Stack trace decoder would indeed help to track down the problem, although with this simple program it probably helps just to tick erase all flash contents. Sometimes things can go wrong in the configuration and circuses happen.

Many thanks for your help @khoam

[Solved] ESP8266MOD: No WiFi connection - program code issues

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#1 19425195 09 May 2021 18:30

dasej dasej

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Post #1
19425195 09 May 2021 18:30

Welcome.

The topic is about this version of the mod
.

Code: C / C++
Log in, to see the code
.

There is practically nothing in the program and it constantly resets itself.
As I do not attach the WiFi support the module itself when blinking the diode works.

Is the module defective or am I doing something wrong?

Code: Ini
Log in, to see the code
.
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#2 19425235 09 May 2021 19:09

sylweksylwina sylweksylwina

Moderator of Computers service

Posts: 13170

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Post #2
19425235 09 May 2021 19:09

Power supply all correct? I.e. you're probably powering from USB anyway, but you could check that the voltages are correct after the stabiliser etc.

Exception indicates a problem with program execution, if it is caused by WiFi code then maybe try clearing memory and uploading new firmware.

rst cause 2 it looks like the reset button was pressed.

Don't do so many delays because if you start to complicate the code, it will start to watchdog reset the board (rst cause 4).
You can give yield() in the main program loop.
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#3 19425289 09 May 2021 19:38

dasej dasej

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Post #3
19425289 09 May 2021 19:38

I fed 3.3V from the power supply behind the stabiliser and still the same.
The button is working, when I hold it down the ESP does not start.
I added a delay so that ESP resets more slowly.
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#4 19425336 09 May 2021 20:07

Anonymous Anonymous

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Post #4
19425336 09 May 2021 20:07

Delay in esp does not exist

Code: C#
Log in, to see the code
.
#5 19425405 09 May 2021 20:55

Anonymous Anonymous

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Post #5
19425405 09 May 2021 20:55

@dasej Install a plug-in for the Arduino IDE called ESP8266/ESP32 Exception Stack Trace Decoder . You will then know specifically where the program is crashing. Otherwise, it's a search in the dark. Link .

Jarzabek666 wrote:
Delay in esp does not exist
.
Really? Code from Arduino Core for ESP8266 below. It is certainly less blocky than what you presented in your post.
Code: C / C++
Log in, to see the code

Added after 4 [minutes]:

sylweksylwina wrote:
Don't do so many delays because if you start complicating the code it will start your watchdog resetting the board
.
Nonsense. The delay() function in the ESP8266 does not block the execution of other threads or the operation of the WTD.
#6 19425450 09 May 2021 21:09

Anonymous Anonymous

Level 1

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Post #6
19425450 09 May 2021 21:09

khoam wrote:
Really? Code from the Arduino Core for the ESP8266 below.

Well I also have from Arduino CORE for ESP8266....

And my general issue is that the delay doesn't block, but flips to other threads Wifi support etc in this WDT....

Sometimes even advisable to use delay in esp....
#7 19425463 09 May 2021 21:19

dasej dasej

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Post #7
19425463 09 May 2021 21:19

@khoam .
I received something like this back.

Code: Ini
Log in, to see the code
.

Added after 1 [minute]:

@Jarzabek666 .

My dear reader, we are not writing here about DELAY.
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Helpful post

#8 19425469 09 May 2021 21:20

Anonymous Anonymous

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Helpful post
Post #8
19425469 09 May 2021 21:20

In the board settings, change "Erase Flash" to "All Flash Contents" and reload the programme.
#9 19425500 09 May 2021 21:35

dasej dasej

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Post #9
19425500 09 May 2021 21:35

@khoam Many thanks works.
Two words of explanation.
#10 19425505 09 May 2021 21:38

Anonymous Anonymous

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Post #10
19425505 09 May 2021 21:38

You can go back to "Only Sketch". The whole process of loading the code will be faster.

Added after 1 [minute]: .

dasej wrote:
Two words of explanation.

There was rubbish in the flash area where the settings for the WiFi network are stored. Unfortunately the WiFi.begin() function doesn't clear this, it just sets those parameters you specified in the program.
#11 19425519 09 May 2021 21:44

sylweksylwina sylweksylwina

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Post #11
19425519 09 May 2021 21:44

Okay I actually got something mixed up, although I try to avoid delays anyway, maybe that's what got me worked up. Although I'll admit honestly that I haven't figured out the basics like delay in the source files.

Stack trace decoder would indeed help to track down the problem, although with this simple program it probably helps just to tick "erase all flash contents". Sometimes things can go wrong in the configuration and circuses happen.
#12 19425532 09 May 2021 21:48

dasej dasej

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Post #12
19425532 09 May 2021 21:48

Many thanks for your help @khoam
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Topic summary

✨ The discussion revolves around issues with establishing a WiFi connection using the ESP8266MOD module. The user provided a code snippet but encountered problems, including exceptions during execution. Responses suggested checking the power supply, clearing memory, and using the "Erase Flash" option in the Arduino IDE to resolve potential issues with residual settings. The importance of minimizing delays in the code to prevent watchdog timer resets was emphasized. Additionally, using the ESP8266/ESP32 Exception Stack Trace Decoder was recommended for debugging. Ultimately, the user found success by erasing all flash contents, which resolved the connection issue.
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ESP8266MOD: No WiFi connection - program code issues

FAQ

TL;DR: A 3-step flash erase fixed the ESP8266 Wi‑Fi resets; "There was rubbish in the flash area." It clears corrupt Wi‑Fi settings that WiFi.begin won’t reset, stopping Exception 3 loops. Then switch uploads back to Only Sketch for speed. [Elektroda, khoam, post #19425505]

Why it matters: This helps makers quickly stop ESP8266 reset loops during Wi‑Fi connect without replacing hardware.

Quick Facts

Typical symptom: Exception (3) with repeated "rst cause:2" messages after WiFi.begin(), seen at 115200 baud. [Elektroda, dasej, post #19425195]
Primary fix: In Arduino IDE, set Erase Flash = "All Flash Contents" and re-upload the sketch. [Elektroda, khoam, post #19425469]
Root cause: Corrupted Wi‑Fi config in flash; "WiFi.begin() doesn't clear this" area. [Elektroda, khoam, post #19425505]
Fast diagnosis: Install the ESP8266/ESP32 Exception Stack Trace Decoder plugin for Arduino IDE. [Elektroda, khoam, post #19425405]
Power sanity-check: Verify a stable 3.3 V after the regulator before chasing firmware issues. [Elektroda, sylweksylwina, #19425235

How do I fix ESP8266 Wi‑Fi resets right after WiFi.begin()?

Erase the saved Wi‑Fi config and re-upload. In Arduino IDE, set Tools → Erase Flash → All Flash Contents. Upload your sketch again. This clears corrupted credentials that trigger resets during connect. It’s the quickest, proven fix in this thread. [Elektroda, khoam, post #19425469]

Why did erasing flash fix the crash?

"There was rubbish in the flash area where the settings for the WiFi network are stored." WiFi.begin() only sets parameters; it does not purge old, corrupt data. Clearing flash removes that bad state so the ESP8266 can associate cleanly. [Elektroda, khoam, post #19425505]

What does "Exception (3) LoadStoreError" mean on ESP8266?

It decodes to: LoadStoreError, a processor internal physical address or data error during load or store. In practice, it shows as a crash with a stack trace. Decode it to see which call path failed. [Elektroda, dasej, post #19425463]

What does "rst cause:2" in the boot log tell me?

It indicates an external reset, like pressing the reset button. Watchdog-triggered resets typically show as cause 4. This helps distinguish a manual reset from firmware stalls. "rst cause 2 it looks like the reset button was pressed." [Elektroda, sylweksylwina, post #19425235]

Which tool decodes ESP8266 exception stack traces in Arduino IDE?

Install the "ESP8266/ESP32 Exception Stack Trace Decoder" plugin. It maps program counters to source lines, making crashes actionable instead of guesswork. This was the recommended approach in the thread. [Elektroda, khoam, post #19425405]

Should I avoid delay() on ESP8266 to prevent WDT resets?

No. "The delay() function in the ESP8266 does not block the execution of other threads or the operation of the WTD." delay() yields internally, so it cooperates with Wi‑Fi and system tasks. [Elektroda, khoam, post #19425405]

Do I need to add yield() in my loop?

Add yield() in tight loops or long operations to keep the system responsive. It prevents watchdog resets when you do extended processing without delays or blocking calls. "You can give yield() in the main program loop." [Elektroda, sylweksylwina, post #19425235]

How can I quickly check if power is the culprit?

Confirm a stable 3.3 V rail after the regulator and proper grounding. Measure under load. If voltage is correct yet crashes persist, investigate firmware and flash content next. The thread began with a power check suggestion. [Elektroda, sylweksylwina, post #19425235]

I powered it with 3.3 V after the regulator and it still resets—what next?

If a clean 3.3 V supply doesn’t help, suspect firmware state. Proceed to erase flash and re-upload. In the thread, external 3.3 V didn’t change the behavior until flash was cleared. [Elektroda, dasej, post #19425289]

What baud rate should I use to read logs and exceptions?

Use 115200 baud. Match Serial.begin(115200) in your sketch and set your Serial Monitor the same. This ensures the boot logs and decoder outputs are readable. [Elektroda, dasej, post #19425195]

After wiping flash, can I speed up uploads again?

Yes. Switch Tools → Erase Flash back to "Only Sketch" after the successful recovery. This shortens upload time while keeping your fresh Wi‑Fi settings. "You can go back to 'Only Sketch'." [Elektroda, khoam, post #19425505]

Is my reset button OK if holding it stops the ESP from starting?

Yes. Holding Reset keeps the chip from booting, which is expected. That confirms the button is wired and functioning. Release it to allow normal boot. [Elektroda, dasej, post #19425289]

Can long blocking code still trigger watchdog resets?

Yes. Long, non-yielding code paths can cause WDT resets, which appear as rst cause 4. Break work into chunks, use yield(), or rely on delay() which yields. [Elektroda, sylweksylwina, post #19425235]

Did this fix actually work for the original poster?

Yes. After setting Erase Flash to All Flash Contents and reloading, the OP confirmed the module worked. They thanked the helper for the solution. [Elektroda, dasej, post #19425500]

Quick how-to: erase ESP8266 Wi‑Fi settings that crash WiFi.begin()

In Arduino IDE, set Tools → Erase Flash → All Flash Contents.
Upload your sketch again.
Let it boot and confirm stable Wi‑Fi connection in Serial Monitor. This removes corrupted credentials and stops the reset loop. [Elektroda, khoam, post #19425469]

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