Tips and tricks and common problems

Network tips and problems

• Missing WebServer
• Websocket
• Switch off Bluetooth and WiFi
• Get stored WiFi AP and STA info
• Ping library
• SSDP - Simple Service Discovery Protocol
• ESPNow not working after connection to WiFi AP
• Missing DNS settings when using static IP
• WiFi connection problem - NVS corrupted
• WiFi Auto Reconnect problems
• WiFi AP and STA active at the same time
• Workaround for WifiClientSecure::connect does not give any certificate-fail clarification

I2C, SPI tips and problems

• How to use stickbreaker’s I2C improved code
• Simultaneously use of two I2C buses - TwoWire interfaces
• OneWire alternative library
• Simultaneously use of two SPI buses

Bluetooth and BLE tips and problems

• Switch off Bluetooth and WiFi
• Initialize Bluetooth Serial and BLE server

ADC and DAC tips and problems

• ADC2 channel cannot be used when WiFi is in use
• analogRead() triggers unrelated interrupt
• Analog Read seems to be slow

SD card tips and problems

• SDFS File::flush() and SD_MMC.flush() appears to do nothing

GPIO tips and problems

• Reserved GPIO’S

Programming tips and problems

• Change global variables from ISR
• Sleep mode examples
• Deep-Sleep needs WiFi and Bluetooth switched OFF for low current consumption
• Multithreading support with xTaskCreate
• /avr-pgmspace.h: No such file or directory
• Important when using the Preferences library - key name length limited to 15 characters!
• Important when using the Preferences library - tag length limited to 1984 characters!

Debugging tips and problems

• Suppress debug output during boot
• Get the last reset reason
• ESP32 application log output in the same format as the core log output

Partition tips and problems

• Change partition size
• Expansion of NVS partition

ESP32 module specific stuff

• TTGOV2 SD card support
• pinMode() on pin 13 causes watchdog reset and CPU freezes afterwards!

Arduino IDE specific

• Alternative to install arduino-esp32 for Arduino IDE (Windows)
• ESP32 framework installation on Windows XP
• get.exe/get.py fails to download required files
• Change partition size (Arduino IDE)
• Add ESP32 to Boardsmanager

PlatformIO specific

• Enable log levels
• Change partition size (PlatformIO)
• Get board name in your code

Common problems

• ESP32 not showing in serial port (MAC Desktop/Laptop problem)
• Problem with Adafruit FONA library
• Upload of code over USB/Serial fails because of erroneous code
• Problems after cloning the repository

Tutorials and Documentation

• the INTERNET of THINGS with ESP32→
• techtutorialsx→
• IoT Sharing→

ESP32 variants and modules

• Espressif ESP-WROOM-32 module→
• ESP-WROOM-32 Pin Definitions
• Espressif ESP32-DevKitC→
• Espressif ESP-WROVER-KIT→
• Chips and modules list→
• Elecrow ESP32 WIFI/BLE Board v0.9 WIKI→
• Elecrow ESP32 WIFI/BLE Board v0.9 Pinout

Installation Instructions

• Arduino IDE
  • Windows→
  • Mac→
  • Debian/Ubuntu→
  • Fedora→
  • openSUSE→
• PlatformIO→
• Building with make→
• Using as ESP-IDF component→
• Building ESP32 toolchain on ARM (Armbian Raspbian)