How to reset ESP on button click (interrupt conflict with wi-fi)

[v11]

Hello all!

Summary
I am working on a e-paper device. The device is using an ESP32 to connect to the Internet over wi-fi. It offers also some buttons for the user to reset the device, to turn it off or to start in BLE mode for device provisioning.

First approach
Since I have a quite long setup routine (up to 30 seconds, before the device is going into deep-sleep) i was attaching interrupts. So for example if the user is clicking the reset button it will trigger ESP.restart().

void setInterrupt() {

    Serial.println("");
    Serial.println("set reset interrupt");

    pinMode(pinRSE, INPUT_PULLDOWN);
    attachInterrupt(pinRSE, resetESP, HIGH);
}

void IRAM_ATTR resetESP() {

    pinMode(pinRSE, INPUT_PULLDOWN);

    ESP.restart();
}

This will result in a Guru Medidation Error:

Guru Meditation Error: Core  1 panic'ed (Interrupt wdt timeout on CPU1). 

Core  1 register dump:
PC      : 0x4009a44e  PS      : 0x00060a35  A0      : 0x8009940e  A1      : 0x3ffbf0bc  
A2      : 0x3fff2f04  A3      : 0x3ffbd8ac  A4      : 0x00000004  A5      : 0x00060a23  
A6      : 0x00060a23  A7      : 0x00000001  A8      : 0x3ffbd8ac  A9      : 0x00000019  
A10     : 0x3ffbd8ac  A11     : 0x00000019  A12     : 0x3ffc7a34  A13     : 0x00060a23  
A14     : 0x007bf2b8  A15     : 0x003fffff  SAR     : 0x0000000c  EXCCAUSE: 0x00000006  
EXCVADDR: 0x00000000  LBEG    : 0x40094280  LEND    : 0x40094296  LCOUNT  : 0xffffffff  
Core  1 was running in ISR context:
EPC1    : 0x4010212f  EPC2    : 0x00000000  EPC3    : 0x00000000  EPC4    : 0x00000000

Backtrace:0x4009a44b:0x3ffbf0bc |<-CORRUPTED
  #0  0x4009a44b:0x3ffbf0bc in vListInsert at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/list.c:183

Core  0 register dump:
PC      : 0x4009a5cd  PS      : 0x00060435  A0      : 0x8009a0ef  A1      : 0x3fff0ac0  
A2      : 0x3ffbf2b8  A3      : 0xb33fffff  A4      : 0x0000abab  A5      : 0x00060423  
A6      : 0x00060423  A7      : 0x0000cdcd  A8      : 0x0000cdcd  A9      : 0xffffffff  
A10     : 0x00000000  A11     : 0x3ffbdd00  A12     : 0x00000001  A13     : 0x00060423  
A14     : 0x007bf2b8  A15     : 0x003fffff  SAR     : 0x0000001f  EXCCAUSE: 0x00000006  
EXCVADDR: 0x00000000  LBEG    : 0x40094280  LEND    : 0x40094296  LCOUNT  : 0xffffffff  

Backtrace:0x4009a5ca:0x3fff0ac00x4009a0ec:0x3fff0b00 0x400987ec:0x3fff0b20 0x4009889c:0x3fff0b60 0x400854ed:0x3fff0b80 0x401ba2e1:0x3fff0ba0 0x401b737f:0x3fff0bd0 0x401b83af:0x3fff0bf0 0x401b6900:0x3fff0c10 0x401f5e41:0x3fff0c30 
  #0  0x4009a5ca:0x3fff0ac00 in esp_ptr_external_ram at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/soc/include/soc/soc_memory_types.h:97
      (inlined by) spinlock_acquire at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/esp_hw_support/include/soc/spinlock.h:99
      (inlined by) xPortEnterCriticalTimeout at /home/runner/work/esp32-arduino-lib-builder/esp32-arduino-lib-builder/esp-idf/components/freertos/port/xtensa/port.c:287

ELF file SHA256: 0000000000000000

I figured it out that i only get this error, when i start a wi-fi connection during setup. I have read that there can be conflicts with interrupts.

Second approach
Then i have read about the topic of tasks running on the second core. I have tried to implement this by having a loop-routine on the second core that constantly checks for button input. And if there is a button press i can trigger ESP.restart().

 xTaskCreatePinnedToCore(
      Task1code, /* Function to implement the task */
      "Task1", /* Name of the task */
      1000,  /* Stack size in words */
      NULL,  /* Task input parameter */
      0,  /* Priority of the task */
      &Task1,  /* Task handle. */
      0); /* Core 

This is working. This time also without Guru meditation error. But then i recognized that the ESP is very slow in computation. My setup routine takes much more time and often it crashes with some memory issues when try to do https requests.

So i am looking for advice:

• What is the propper way to handle button input when using wifi? Keep in mind, i don't have a loop function because right after setup is done, the device goes into deep sleep.
• Can somebody explain if I am doing something wrong with my second apporach? Why is ESP so slow and has memory issues?

Thank you in advance for your help.

Here is my platform.ini

[env:esp32dev]
framework = arduino
platform = espressif32@4.2.0
board = esp32dev
board_build.f_cpu = 240000000L
board_build.partitions = min_spiffs.csv
board_build.f_flash = 80000000L
upload_speed = 115200
monitor_speed = 115200
build_type = debug
monitor_filters = esp32_exception_decoder
lib_deps = 
	vroland/epdiy@^1.0.0
	bblanchon/ArduinoJson@^6.19.4
	makuna/NeoPixelBus@^2.6.9
	arkhipenko/TaskScheduler@^3.7.0
build_flags = 
	-DBOARD_HAS_PSRAM
	-mfix-esp32-psram-cache-issue
	-DCONFIG_EPD_BOARD_REVISION_V5
	-DCONFIG_EPD_DISPLAY_TYPE_ED097OC4
	-DCONFIG_ARDUINO_ISR_IRAM=1

[me-no-dev]

the problem is that you are trying to reset from an interrupt. You should instead set a flag (which you can check in a loop with some delay) or use semaphore for which you can wait in a loop and trigger reset from the task

[v11]

Yes, i can try this again.

But have you seen my issues (see second approach) what happens when i am starting another task? Do you also think that is related that i am using ESP.restart() in that second task?

[me-no-dev]

your issue was that you were restarting from the interrupt callback. When doing through task, you said it's restarting OK?

[v11]

Yes, restarting is ok with my second approach. But i am running into memory issues and very poor performance. Which i have no idea where thy come from.

[me-no-dev]

are you delaying between checks in that other task? if you just loop check without delay, you are keeping the CPU busy, so delay(100) is good approach

[v11]

Will try! Thank you! 👍🏻

[v11]

This is how i create the task:

xTaskCreatePinnedToCore(
      Task1code, /* Function to implement the task */
      "Task1", /* Name of the task */
      1024,  /* Stack size in words */
      NULL,  /* Task input parameter */
      0,  /* Priority of the task */
      &Task1,  /* Task handle. */
      1); /* 

This is my task

void Task1code( void * parameter) {
  for(;;) {
    delay(100);
     if(digitalRead(pinRSE) == HIGH) {
        if(!buttonCheck && bleState == 0) {
            ESP.restart();
            buttonCheck=true;
        }
    
    }
  }
}

And then i get the following error in my log:

load bitmap from firebase storage
connect to server via port 443
[ 12683][E][ssl_client.cpp:36] _handle_error(): [start_ssl_client():263]: (-16) BIGNUM - Memory allocation failed
[ 12683][E][WiFiClientSecure.cpp:135] connect(): start_ssl_client: -16
connection failed with error: BIGNUM - Memory allocation failed

I am wondering how to define the correct stack size value. But at least the speed issues are gone.

[v11]

This is a part of debug:

get device config from firebase
connect to server via port 443
[  4182][V][ssl_client.cpp:61] start_ssl_client(): Free internal heap before TLS 56160
[  4186][V][ssl_client.cpp:67] start_ssl_client(): Starting socket
[  4319][V][ssl_client.cpp:143] start_ssl_client(): Seeding the random number generator
[  4322][V][ssl_client.cpp:152] start_ssl_client(): Setting up the SSL/TLS structure...
[  4325][I][ssl_client.cpp:173] start_ssl_client(): WARNING: Skipping SSL Verification. INSECURE!
[  4332][V][ssl_client.cpp:244] start_ssl_client(): Setting hostname for TLS session...
[  4340][V][ssl_client.cpp:259] start_ssl_client(): Performing the SSL/TLS handshake...
[  5514][V][ssl_client.cpp:280] start_ssl_client(): Verifying peer X.509 certificate...
[  5514][V][ssl_client.cpp:288] start_ssl_client(): Certificate verified.
[  5517][V][ssl_client.cpp:303] start_ssl_client(): Free internal heap after TLS 13440
requesting url: *******************
[  5537][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 61 bytes...
[  5546][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 2 bytes...
[  5553][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 6 bytes...
[  5560][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 59 bytes...
[  5568][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 2 bytes...
[  5576][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 17 bytes...
[  5584][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 2 bytes...
[  5591][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 17 bytes...
[  5602][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 2 bytes...
[  5606][V][ssl_client.cpp:351] send_ssl_data(): Writing HTTP request with 2 bytes...
http response: 200 ok
serialization successful
received: channel: beta
received: display type: 9in7_16grey
received: timezone: CET-1CEST,M3.5.0,M10.5.0/3
received: timezone location: Europe/Zurich
received: deep sleep in seconds: 3600
[  5707][V][ssl_client.cpp:311] stop_ssl_socket(): Cleaning SSL connection.
check client channel with server channel
server channel identical - keep client channel: beta
check display type with server display type
server display type identical - keep client display type: 9in7_16grey
[  5729][V][ssl_client.cpp:311] stop_ssl_socket(): Cleaning SSL connection.
Heap: 57888

load bitmap from firebase storage
Heap in Render Bitmap HTTPS: Before Client57888
Heap in Render Bitmap HTTPS: After Client56228
Heap in Render Bitmap HTTPS: After Client insecure56228
connect to server via port 443
[  5754][V][ssl_client.cpp:61] start_ssl_client(): Free internal heap before TLS 56228
[  5761][V][ssl_client.cpp:67] start_ssl_client(): Starting socket
[  6010][V][ssl_client.cpp:143] start_ssl_client(): Seeding the random number generator
[  6012][V][ssl_client.cpp:152] start_ssl_client(): Setting up the SSL/TLS structure...
[  6014][I][ssl_client.cpp:173] start_ssl_client(): WARNING: Skipping SSL Verification. INSECURE!
[  6023][V][ssl_client.cpp:244] start_ssl_client(): Setting hostname for TLS session...
[  6031][V][ssl_client.cpp:259] start_ssl_client(): Performing the SSL/TLS handshake...
[  6594][E][ssl_client.cpp:36] _handle_error(): [start_ssl_client():263]: (-16) BIGNUM - Memory allocation failed
[  6594][E][WiFiClientSecure.cpp:135] connect(): start_ssl_client: -16
[  6603][V][ssl_client.cpp:311] stop_ssl_socket(): Cleaning SSL connection.
connection failed with error: BIGNUM - Memory allocation failed
[  6617][V][ssl_client.cpp:311] stop_ssl_socket(): Cleaning SSL connection.
Heap: 58088

get time
1673450971

Does this help? You can see another HTTP request before which is not failing.

[mrengineer7777]

[  4340][V][ssl_client.cpp:259] start_ssl_client(): Performing the SSL/TLS handshake...
[  5514][V][ssl_client.cpp:280] start_ssl_client(): Verifying peer X.509 certificate...
[  5514][V][ssl_client.cpp:288] start_ssl_client(): Certificate verified.
[  5517][V][ssl_client.cpp:303] start_ssl_client(): Free internal heap after TLS 13440

1.2s for handshake. 13440 bytes remaining. 42720 bytes used. Yikes!

[  6031][V][ssl_client.cpp:259] start_ssl_client(): Performing the SSL/TLS handshake...
[  6594][E][ssl_client.cpp:36] _handle_error(): [start_ssl_client():263]: (-16) BIGNUM - Memory allocation failed

5.6s for handshake. Memory allocation (on heap?) fails. This can happen if heap is fragmented. Check largest contiguous block before the second HTTP call:

uint32_t maxblock = ESP.getMaxAllocHeap();
log_i("Heap   Contig %u", maxblock);

Note this number will be smaller than ESP.getFreeHeap().

[v11]

This is the result:

load bitmap from firebase storage
[ 11272][I][main.cpp:1775] renderBitmapFromHTTPS(): Heap   Contig 47092
Heap in Render Bitmap HTTPS: Before Client58072
Heap in Render Bitmap HTTPS: After Client56212
Heap in Render Bitmap HTTPS: After Client insecure56212

Just for context: I am somewhere in the alps and my mobile connection is bad. That is maybe the reason for the long delays.

[mrengineer7777]

47092 < 42720. So close! However I don't see a failure there. [Edit: That's a 7 not a 2. I can't read.]

I imagine the allocation request that fails is smaller than that. We probably won't know, as I believe it's done by an external library (MBED TLS).

[mrengineer7777]

Either way, you should look at reducing your heap memory usage.

[mrengineer7777]

Task stack size:
https://www.freertos.org/FAQMem.html#StackSize
https://www.freertos.org/a00110.html#configMINIMAL_STACK_SIZE

For esp32:

FreeRTOSConfig.h:

#define configSTACK_OVERHEAD_TOTAL (                                    \
                                    configSTACK_OVERHEAD_CHECKER +      \
                                    configSTACK_OVERHEAD_OPTIMIZATION + \
                                    configSTACK_OVERHEAD_APPTRACE +     \
                                    configSTACK_OVERHEAD_WATCHPOINT     \
                                                                        )

#define configMINIMAL_STACK_SIZE                        (768 + configSTACK_OVERHEAD_TOTAL)

sdkconfig.h #define CONFIG_FREERTOS_WATCHPOINT_END_OF_STACK 1
Working through all defines, configMINIMAL_STACK_SIZE = 768 + 60 = 828.

printf("Min stack = %u\r\n", configMINIMAL_STACK_SIZE);
13:08:28.134 > Min stack = 828

Confirmed.

[v11]

Thank you. I am not sure what you want to point out with your latest post. Can you elaborate?
In the meantime i am trying to reduce heap by turn off wi-fi in the right moment etc. Maybe i find some other ideas to reduce heap during runtime. So far i can understand, this is the main issue.

[mrengineer7777]

I am wondering how to define the correct stack size value. But at least the speed issues are gone.

Answer: minimum 828 (words).

[v11]

Thanks. It seems I need to go step by step and check where i can save some ram.