Compilation issues

Issues in libraries compilation
I decided to upgrade an infrastructure of few projects built from Arduino Nano and nRF24L01+ to ESP32 with LoRa transceiver. The aim enhancement of both communication range and processing power.

For the development I purchased few units of WiFi LoRa 32 V2 and Wireless stick (LoRa WiFi BLE), all from Heltec. My environment is Windows 10 and Arduino IDE 1.8.2. The ESP32 is connected through 15cm long cable to USB2.0 port.

All the experiments described below were done on 4 units, 2 of every part. I also uninstalled and re-installed the IDE.

I’d appreciate very much any clue.

I used the LoRaDumpRegisters example from The problem is as listed in the table below. All other references to both Heltech and LoRa libraries were OK.

\Users\USER\AppData\Local\Temp\arduino_build_287169\ sketch\LoRaDumpRegisters.ino.cpp.o:(.literal._Z5setupv+0x4) undefined reference to `Heltec’
\Users\USER\AppData\Local\Temp\arduino_build_287169\ sketch\LoRaDumpRegisters.ino.cpp.o:(.literal._Z5setupv+0x8) undefined reference to `Heltec_ESP32::begin(bool, bool, bool, bool, long)’
\Current\ESP32comm\LoRaDumpRegisters/ LoRaDumpRegisters.ino:20 undefined reference to `Heltec_ESP32::begin(bool, bool, bool, bool, long)’

Please try to update the library, update the IDE or check the configuration (refer to Documentpage). I tried to compile without problems。

Dear Xiao-h,
Thank you very much for your kind and helpful advice.

Following it I reinstalled the IDE with the board package and built-in library. I want now to download a fresh copy of the Heltec library; however, the GIT contains two libraries: Heltec_ESP32-Dev-boards and Heltec_ESP32-master. The same .json file is included in both libraries, although the copyright notice inside the .h files ans its sizes are different.

  1. Is there any recommendation for the most advised library?

  2. Both libraries are using the IDE built-in <arduino.h>, <SPI.h>, <wire.h> and <Arduino.h> that are of the Arduino, so alternatives should be used.Are there any recommendations?

Thank very for your kind advice,

Solved after modifying some of the methods. I used Heltec Master Library with the built-in libraries. Thank you