Example compilation fail for SAMD21 in Arduino IDE

[bobricius]

Hi, I am beginner in this high level programing,
I try compile this library in Arduino IDE for Armachat project with SAMD21 (etc Arduino Zero)
I get lot of errors and I have no idea how to fix.
Including errors in file.
error.txt
Can anybody help?
THANKS

[paidforby]

The most likely problem is that you need to #define ARDUINO_LORA as described here https://github.com/sudomesh/LoRaLayer2#api.

If you are using the example code, you may be able to place #define ARDUINO_LORA at the very top of the main.ino file. This is meant to be done in the platformio.ini file using a build flag. I'm not sure if it is possible to add a build flag in the Arduino IDE.

[paidforby]

It looks like there might be a way to add compiler flags in a boards.txt or platform.txt file. The extra flag you would need to add is -DARDUINO_LORA. Sorry I can't be of more help, I don't use the Arduino IDE much these days. I highly recommend trying out platformIO, I bet they support your board. A quick search produced these results, https://docs.platformio.org/en/latest/platforms/atmelsam.html and https://docs.platformio.org/en/latest/boards/atmelsam/sparkfun_samd21_mini_usb.html

[bobricius]

Thanks for reply, I already add #define ARDUINO_LORA but nothing changed
also memcpy are udeclared, I try add
#include <stdio.h>
#include <string.h>
anywhere but no change :(

[paidforby]

Those memcpy's and memcmp's are throwing errors because the correct header is not being included which is happening because ARDUINO_LORA is not being defined at a global level (i.e. at compile time).

I guess a solution could be to make ARDUINO_LORA the default by adding a guard at the top of Layer1_LoRa.h and LoRaLayer2.h that would define ARDUINO_LORA as long as the other two options (RL_SX1276 and SIM) are not defined. I'll give this a shot and let you know if it works.

[paidforby]

That solution doesn't appear to work for me in platformio, it causes linker errors now. I don't think there is a good work around to not using a build flag. By creating a default setting, I can now compile, but I am not able to link. I'm not sure why the linker errors are happening, but I'm guessing it doesn't like ARDUINO_LORA not being globally defined.

[bobricius]

I included
#define ARDUINO_LORA
in to LoRaLayer2.h and Layer1_LoRa.h
and errors are reduced only to:
sketch\router_beacon.ino.cpp.o: In function `setup':

D:\arduino-1.8.8-d11\portable\sketchbook\router_beacon/router_beacon.ino:23: undefined reference to `Layer1Class::Layer1Class()'

D:\arduino-1.8.8-d11\portable\sketchbook\router_beacon/router_beacon.ino:24: undefined reference to `Layer1Class::setPins(int, int, int)'

D:\arduino-1.8.8-d11\portable\sketchbook\router_beacon/router_beacon.ino:25: undefined reference to `Layer1Class::setLoRaFrequency(unsigned long)'

D:\arduino-1.8.8-d11\portable\sketchbook\router_beacon/router_beacon.ino:26: undefined reference to `Layer1Class::init()'

libraries\LoRaLayer2\LoRaLayer2.cpp.o: In function `LL2Class::daemon()':

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:573: undefined reference to `Layer1Class::getTime()'

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:581: undefined reference to `Layer1Class::getTime()'

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:582: undefined reference to `Layer1Class::transmit()'

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:587: undefined reference to `Layer1Class::getTime()'

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:588: undefined reference to `Layer1Class::spreadingFactor()'

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:597: undefined reference to `Layer1Class::receive()'

D:\arduino-1.8.8-d11\portable\sketchbook\libraries\LoRaLayer2\src/LoRaLayer2.cpp:577: undefined reference to `Layer1Class::getTime()'

collect2.exe: error: ld returned 1 exit status

exit status 1
Error compiling for board MattairTech MT-D21E (rev B).

[bobricius]

I am using this LoRa Library https://github.com/sandeepmistry/arduino-LoRa

[paidforby]

Yes, those are the linker errors I was talking about.

Ok, so I've found the solution. You need to put the compiler flag in a file named platform.local.txt in the same directory where platform.txt is stored. For me, this looks like, ~/Downloads/arduino-1.8.13-linux64/arduino-1.8.13/hardware/arduino/avr because I'm on Ubuntu just running arduino from the folder where I downloaded it, so it may look different for you.

In the platform.local.txt file, you need to put compiler.cpp.extra_flags=-DARDUINO_LORA. That will get rid of all the errors except one about a Serial.printf in Layer1_LoRa on line 155, you can comment that line out and it should compile. Idk why Serial.printf would not be working, that is "standard" Arduino, that needs to be investigate into further.

For reference, I found that solution here, https://stackoverflow.com/questions/28037491/arduino-1-0-6-how-to-change-compiler-flag

[bobricius]

same erros as above
D:\arduino-1.8.8-d11\portable\sketchbook\router_beacon/router_beacon.ino:23: undefined reference to `Layer1Class::Layer1Class()'
..... and more
much less than without #define ARDUINO_LORA in .h files