Developing in C for the ATmega328P: Comparison of Languages

Where I comment on the differences between developing code using Standard C vs using the Arduino Framework.

Introduction

The goal of the AVR C content is to demonstrate how you are able to develop code in C without the Arduino Software Framework. This note is intended to show specifically, the differences in code development between the two. I don’t believe one is intrinsically better than the other as I believe, each one has strong positive traits related to its goals.

Embedded Language Overview

Its best to start by understanding the different language/development environments is directly related to embedded systems development. In this comparison, I’ll talk about four distinct languages/environments in the development of applications on an embedded microcontroller.:

1. Python(MicroPython/CircuitPython): An interpreted language with a Read-Eval-Print-Loop (REPL) which provides for extremely fast prototyping with a comparatively slow execution speed as well as significant memory requirements. Python is a friendly language, which means it is easy to read, easy to write and ubiquitous. It does have significant memory requirements so one can’t use it on the ATmega328P. I would recommend it for someone that is more interested in getting a larger project accomplished where the microcontroller is a means to the end.
2. Arduino Software Framework: This framework brings in a combination of C/C++/Arduino Classes to create a friendly environment for beginning programming. Because of the support provided by Arduino and their supporters, programming via the Arduino framework can be as friendly as Python. While its memory requirements are much less than that of Python, it tends to be slower than using C. This isn’t an issue on the ATmega328P as much as it is an issue on any of the ATtiny processors. I would recommend it to be viewed in the same way as Python. It is not a standards-based approach, which causes issues in university-level instruction.
3. C Language using avr-gcc/avrdude tool chain: A little less friendly than the previous two. It requires understanding the command line regardless of platform (Linux, macOS, or Windows) and a bit more searching to find the answers. This approach is identical to the approach software developers use for developing commercial products, so there are little technical restraints to how or where it can be used. I would recommend it to someone that wants to understand the microcontroller as much as they want to accomplish a project. If someone is early in their career and wishes to become an engineer developing products with microcontrollers, this is the way to go.
4. Forth Language: I’ll include this one as it might appeal to a select few that are looking for the functionality of a REPL with the speed and memory requirements of C. What it doesn’t have is the support framework of any of the above 3 approaches, which make it a tough slog at times. While this approach is esoteric, it can be the most rewarding for a technical-minded person.

Arduino IDE to Standard C Translation

Here is a table, where I attempt to show the differences and similarities between using the Arduino Framework and the Standard C approach.

File Template

Arduino

filename.ino

void setup() {
  // put your setup code here, to run once:

}

void loop() {
  // put your main code here, to run repeatedly:

}

Standard C

main.c

/* Document what this program does, include req'd hardware changes
*/

/* Put your #includes here */
#include <stdio.h>
#include <stdlib.h>


/* Put your global variables here */

/* Main - is the function which C will look for to run at initialization*/ 
int main() {
/* initialize code goes here, similar to setup in the Arduino*/

// while(1) loop routine runs over and over again forever:
    while(1) {
        // this is the primary code section to execute
    }
    return0; /* Required for strict C implementation
}