Given that we understand the motivation behind Servio (as gleaned from the first log), let's delve deeper into its anatomy and other relevant aspects. These logs will contain some redundancy, as it does not neatly divide into parts but instead examines the subject from multiple perspectives.

This comprehensive overview will be released in five parts to avoid overwhelming readers with one lengthy log. Enjoy!

Project's Perspective

Servio can be viewed as a set of projects with varying degrees of independence. Each project has its own repository. There are two core projects: servio and servio(private). Servio is formed by an open-source public component (firmware, some utilities, some tests) and a private component (numerous tests). We tend to view these components as two intertwined projects that need to coexist.

In addition to these, we maintain some C++ libraries that we developed. These include `emlabcpp`, a generic embedded-related library, and `joque`, an utility library used by the private part of Servio. The rest of this section will provide more detailed descriptions of each project.

During early development, yaqwsx provided me with two PCB designs for prototyping (versions 1 and 2), both available in a standalone PCBs repository. Recently, Tomas Vavrinec agreed to design another prototype board. Overall, various PCB design projects are associated with Servio.

servio

This is the public component of Servio and the project's central part (link). It includesthe entire firmware. The firmware depends only on the emlabcpp library and the standard C++ library, making it fully open-source. Additionally, there is a command-line utility for working with the servo `scmdio`, a basic set of unit tests, and black-box tests.

This should suffice for users who wish to modify the servo's code or inspect what they are using in their hardware. We will discuss the source code structure in greater detail later in another logs.

servio(private)

Our private repository contains our testing infrastructure and some glue that connects everything together.

Our testing infrastructure is capable of executing various types of tests (currently including unit tests, firmware tests, control tests, simulation tests, and black-box tests) adn generate HTML reports for analysis.

The challenge with both servio repositories is their separate yet tightly coupled nature. This requires us to maintain tight synchronization, which can be challenging.

In a future log, we will explain why we undergo this public/private separation.

emlabcpp

emlabcpp, a few years older than Servio, is an opinionated C++20 library focused on embedded-related utilities. It emphasizes providing numerous small utilities or mini-libraries for embedded code.

The embedded-related aspect implies code with a low footprint that avoids dynamic memory and exceptions. Servio is built upon this library, which was expanded with utilities necessary for Servio during its development. Most notably, it includes an embedded-focused testing library for tests executed on the target hardware.

joque

joque is a small library designed to parallelly execute a set of tasks while respecting their dependencies. It's what we use to orchestrate tests.

Generally, when feasible, I prefer to create a few smaller libraries from the project for future reuse.

PCBs v1, v2, and v3

We have separate repositories for PCB designs, primarily for development boards. These are somewhat standalone, especially the latest version, v3, designed by T. Vavrinec for us, though the repository remains his. v2 exists here, and v3 is here.

This independence applies only to the hardware design files. The software side must be compatible with the boards (pin assignments) and is currently stored in the main repository.