avr-gcc vs Arduino in PlatformIO

Question

I'm using PlatformIO as an IDE for programming AVR MCUs. I'm beginning AVR programming (I have a background in C/C++ and programming on OS's, not embedded, although I have done some Arduino stuff in the past) and using PlatformIO gives me code completion for the registers/pins, which is why I use it.

It seems I can't switch framework from Arduino to avr-gcc in PlatformIO without losing code-completing.

I am wondering if there's any drawbacks in keeping Arduino as the framework?

I know Arduino uses avr-gcc in the back, but I read that it still does a bit of setup without the users knowing it (such as Timer0 setting for delays, which I need since I'm using it as a clock source for USI on my ATTiny85).

Otherwise, is there anyway in PlatformIO to keep code completion and use avr-gcc instead of Arduino?

Thanks!

EDIT: I'm on either OSX or linux (ubuntu).

Answer 1

As pointed out by ivankravets on the PlatformIO community platform (see: https://community.platformio.org/t/avr-programming-without-arduino-framework/525/4), it is as simple as removing the line framework = arduino from the platformio.ini file to get rid of the Arduino framework and work in bare C for avr-gcc.

Answer 2

I have never used PlatformIO, and my answer is only based on my (extended) knowledge of AVR development and the Arduino mess…err…framework.

The Arduino framework is using AVR-libc (the standard low level framework that gives you all the tools you need to program on AVR), and adds a layer of abstraction so you're not directly handling registers, but use a more easily understandable interface.

So when you write on a pin, instead of looking at the AVR's IC leg number, looking for the matching PORT address to configure it and mutate it, you're using digitalWrite() on the board's pin number. So, whatever the IC is, the pin will stay the same with consistent capabilities.

The pin definition is done using a header file that's given to the compiler depending on your target setting in your IDE (so whether you use an Arduino Mega or a Leonardo the matching between AVR port/pin and board pinout will change radically).

Given your description of PlatformIO, it's using that information to give you appropriate pinout completion based on the board configuration. It's also certainly taking advantage of the object oriented approach of the Arduino framework, so that you can easily have method completion when using singletons (like when you use Serial).

Using raw AVR-libc, on the other hand, it's harder to get any meaningful completion, because most of the operations are being done on registers which are being declared through preprocessors aliases, and the whole code is pure C, so code completion is not really helpful (you cannot list all the methods that applies to a given object… like with the Serial example).

Then, Arduino offers a nice high level approach to prototyping embedded code, that you can then curate when you need to optimise in time and/or space. And some projects (like the Marlin firmware for repraps) use some sort of hybrid approach, reimplementing many parts of the Arduino interface in a more optimised way (like digitalWrite or the Serial object).

In the end, my advice to you would be to drop platform.io or the arduino IDE, and switch to eclipse if you're really into IDE GUIs, or better, use your preferred powerful editor (like vim/nvim, emacs, atom, sublime…) to have it handle AVR code like any other C code.