Use xTaskCreatePinnedToCore(), internet search time. BTW xTaskCreatePinnedToCore works just like xTaskCreate().

There is this thingy that is an add on to the Arduino IDe called ESP Exception Decored which can be found here https://github.com/me-no-dev/EspExceptionDecoder that has been, for me, a great help in getting to the cause of those Guru error thingies. Why not post your code with code tags so i don't h...

Will the built in pulse counter work for your application?

from the ESP32 PCNT API: The PCNT (Pulse Counter) module is designed to count the number of rising and/or falling edges of an input signal.

https://docs.espressif.com/projects/esp ... /pcnt.html

Are the RPI and ESP32 sharing the same ground?

Have you done a loopback test on the RPi to insure the RPi can send receive serial?

The u8g2 library works on the SH1106 OLED, https://github.com/olikraus/u8g2/wiki Example of a sh1106 instantiation, U8G2_SH1106_72X40_WISE_F_4W_HW_SPI u8g2(U8G2_R0, /* cs=*/ 10, /* dc=*/ 9, /* reset=*/ 8); Select an instantiation that matches your OLED. You can see the default pin numbers/connection...

I did 2 things, a few days ago, that increased the MQTT connection reliability. void MQTTkeepalive( void *pvParameters ) { MQTTclient.setKeepAlive( 90 ); // setting keep alive to 90 seconds for (;;) { if ( (wifiClient.connected()) && (WiFi.status() == WL_CONNECTED) ) { //log_i( "staying alive " ); x...

I use the MQTT keep alive to detect a lack of network connection with MQTT. #include <WiFi.h> #include <PubSubClient.h> #include "certs.h" #include "sdkconfig.h" #include "esp_system.h" #include "freertos/FreeRTOS.h" #include "freertos/task.h" #include "freertos/timers.h" #include "freertos/event_gr...

https://docs.espressif.com/projects/esp ... index.html see Storage.

Well cool, that code, posted above, the ESP32 stayed connected for 24 hours. A first. Seems the MQTT callback does not like to run code.

In this thread I posted code that uses the hardware timer and other libraries https://esp32.com/viewtopic.php?f=19&t=16109