AVR Freaks

As for Why, I am seeking to create a version of the project with no direct Arduino dependencies (that is, I'll replace the few existing Arduiino dependencies with project-specific equivalents.)

I am not in a position to post the source code for the project (and in any event, it's on the large side, so I think given any additional error description beyond a one sentence error message, I should be able fix the issue.)

I just created a trivial application (blink the LED on the target's PC board with delay() in loop, which makes use of the Arduino's run-time environment for timer 0) with Arduino IDE, imported it into Atmel Studio 7 using the procedure I noted first above, and it important, built and ran just as expected (creating the simple main/init/setup/loop construct that populates Arduino applications.)

It appears Atmel Studio copied the referenced Arduino Core directory into the project (and for my project, all of the dependencies of concern live there), so I now have a feel for how the process should work, but am still concerned about the unhelpful error message (several thousand lines of code means there are plenty of places for something the import utility is rejecting!)

Thanks again!

Dave

Thanks, Clawson - I've found the .o files produced by the two different build environments; they're almost all significantly larger with Atmel Studio 7's build.

Current problem: I think I am not successfully setting Atmel Studio 7 to "release" configuration for the solution and it's two projects (one project is the sketch, the other project is Arduino core.)

Solution Explorer -> Solution (first item) -> Properties -> Configuration Properties, I have Configuration: set to Release, and both project contexts reflect Configuration (drop down list) Release

When I go to Arduino Core (one of the two projects in the solution) > Properties, then go to the tab Arduino Core, I find the following

Build section > Configuration > Active (Debug)

Build events section > Configuration > Active (Debug)

Toolchain section > Configuration > Active (Debug)

I then changed Build section to Release (this caused the other two sections to change to Release), found the same and did the same for my imported Sketch part of the solution (so all of the places I have looked now have Release configuration, not Debug configuration), then did File > Save All, exited Atmel Studio 7, then restarted it.

After restart,

Solution Explorer -> Solution (first item) -> Properties -> Configuration Properties, it is set to Release.

When I go to Arduino Core (one of the two projects in the solution) -> Properties, then go to the tab Arduino Core, I find the following

Build section > Configuration > Active (Debug)

Build events section > Configuration > Active (Debug)

Toolchain section > Configuration > Active (Debug)

Same for the Sketch part of the solution.

When I set both Build sections to Release (again), and then look at the two "Debugging" option areas for AVR/GNU C and AVR/GNU C++, I find they are set at Debug level: Default (-g2). I manually changed these to None (in all four places, two for each project), while the Build sections were set for Release, re-did the build, and got the same flash memory size as I had from the beginning, as if nothing I've done so far has any effectd.

For this reason, I'm not certain if I'm successfully building for Debug or Release configuration (I'd imagine Debug creates larger flash sections.)

Thanks for any pointer as to where to look next!

Dave

Got the problem of Debug vs Release fixed - user error - the place I realized to set this is in the "ribbon" at the top of the main window, not in the project or solution properties. I now can switch configurations; Debug adds about 3% to the flash size requirement which seems reasonable.

Now on to the question of how I can enable link time optimization to my Atmel Studio 7 project Release settings.

After je_ruud posting (I hadn't encountered this option before), I was able to disable Link Time Optimizaiton in Arduino IDE and that caused the flash requirement to expand significantly (close enough to the Atmel Studio 7 current result that I'm pretty sure this has been the culprit).

Now I would like to enable link time optimization in Atmel Studio Release configuration. As je_ruud pointed out, this would break debugging, but for release there's no need for debugging, but a significant need to minimize flash occupancy, so that seems like a reasonable trade-off to me.

I've looked through the Toolchain settings and found the following (same for the two projects in the solution, so just examining the settings for the application's project as this is the bulk of the code):

AVR/GNU C Compiler All Options:

-x c -funsigned-char -funsigned-bitfields -DNDEBUG -DF_CPU=16000000L -DARDUINO=108016 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -DUSB_VID=0x2341 -DUSB_PID=0x0043 -DUSB_MANUFACTURER="\"Arduino LLC\""  -I"C:\Program Files (x86)\Atmel\Studio\7.0\Packs\Atmel\ATmega_DFP\1.7.374\include" -I"C:\Users\user\Desktop\r102w-ms7\r102w-ms7\r102w-2\..\ArduinoCore\include\core" -I"C:\Users\user\Desktop\r102w-ms7\r102w-ms7\r102w-2\..\ArduinoCore\include\variants\standard"  -Os -fno-threadsafe-statics -ffunction-sections -fdata-sections -fpack-struct -fshort-enums -g2 -w -mmcu=atmega328p -B "C:\Program Files (x86)\Atmel\Studio\7.0\Packs\Atmel\ATmega_DFP\1.7.374\gcc\dev\atmega328p" -c -std=gnu99 -std=gnu11 -MD -MP -MF "$(@:%.o=%.d)" -MT"$(@:%.o=%.d)" -MT"$(@:%.o=%.o)"

AVR/GNU C++ Compiler All Options:

-funsigned-char -funsigned-bitfields -DNDEBUG -DF_CPU=16000000L -DARDUINO=108016 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -DUSB_VID=0x2341 -DUSB_PID=0x0043 -DUSB_MANUFACTURER="\"Arduino LLC\""  -I"C:\Program Files (x86)\Atmel\Studio\7.0\Packs\Atmel\ATmega_DFP\1.7.374\include" -I"C:\Users\user\Desktop\r102w-ms7\r102w-ms7\r102w-2\..\ArduinoCore\include\core" -I"C:\Users\user\Desktop\r102w-ms7\r102w-ms7\r102w-2\..\ArduinoCore\include\variants\standard"  -Os -fno-threadsafe-statics -ffunction-sections -fdata-sections -fpack-struct -fshort-enums -g2 -w -mmcu=atmega328p -B "C:\Program Files (x86)\Atmel\Studio\7.0\Packs\Atmel\ATmega_DFP\1.7.374\gcc\dev\atmega328p" -c -std=gnu++11 -MD -MP -MF "$(@:%.o=%.d)" -MT"$(@:%.o=%.d)" -MT"$(@:%.o=%.o)"

AVR/GNU Linker All Options:

-Wl,-Map="$(OutputFileName).map" -Wl,--start-group -Wl,-lm  -Wl,--end-group -Wl,--gc-sections -mmcu=atmega328p -B "C:\Program Files (x86)\Atmel\Studio\7.0\Packs\Atmel\ATmega_DFP\1.7.374\gcc\dev\atmega328p" -Os

I didn't find any references to link time optimization among these.

Here's where I found enough clues about Link Time Optimization for Arduino IDE to enable me to remove those options temporarily:

https://forum.mysensors.org/topi...

As the person writing this page was seeking to add Link Time Optimization, the following changes were made (to Arduino IDE at the time):

compiler.c.extra_flags=-flto -fno-fat-lto-objects
compiler.c.elf.extra_flags=-flto -fuse-linker-plugin
compiler.S.extra_flags=-flto
compiler.cpp.extra_flags=-flto
compiler.ar.cmd=avr-gcc-ar

Does this provide appropriate guidance for enabling -flto and friends in Atmel Studio 7's GCC settings?

Thanks again!

Dave