• ARM Cortex-M RTOS Context Switching

    by Chris Coleman

    In this article we will explore how context switching works on ARM Cortex-M MCUs. We will discuss how the hardware was designed to support this operation, features that impact the context switching implementation such as the Floating Point Unit (FPU), and common pitfalls seen when porting an RTOS to a platform. We will also walk through a practical example of analyzing the FreeRTOS context switcher, xPortPendSVHandler, utilizing gdb to strengthen our understanding.

  • The Best and Worst GCC Compiler Flags For Embedded

    by Chris Coleman

    In this article we will explore some of the best and worst compiler flags for GCC (and Clang). Our focus will be on flags used for embedded projects but the reasoning applies to other development environments as well. We will explore the impact each flag has by walking through practical C code examples.

  • Embedded C/C++ Unit Testing Basics

    by Tyler Hoffman

    In this post, we go into detail on how to properly build abstractions to stub, fake, and mock out implementations of low level embedded software and provide a full real-world example of a unit test using the CppUTest 3.8 unit test framework.

  • A Practical Guide to BLE Throughput

    by Chris Coleman

    In this article, we dive into the factors which influence BLE throughput. We will walk through the BLE protocol stack from version 4.0 to 5.1. We will discuss how to audit what is limiting throughput in a BLE connection and parameters which can be tuned to improve it. Finally, we will walk through a couple practical examples where we evaluate and optimize the throughput of a connection.

  • Building Better Firmware with Continuous Integration

    by François Baldassari

    In this post, we introduce Continuous Integration as a modern technique to allow larger teams to move fast without breaking things. We’ll explain what Continuous Integration is, why you may want to use it, and walk you through setting up CircleCI on a firmware project step by step.

  • A Practical guide to ARM Cortex-M Exception Handling

    by Chris Coleman

    In this article we will dive into the details of how the ARM Cortex-M exception model supports the handling of asynchronous events. We will walk through different exception types supported, terminology (i.e. NVIC, ISR, Priority), the configuration registers used & common settings, advanced topics to be aware of regarding exceptions and a few examples written in C.

  • Building a CLI for Firmware Projects using Invoke

    by Tyler Hoffman

    Building a small (or large) command line interface (CLI) for a project is a great way to get an entire team to build, test, debug, and work with a project in the same way using the same set of tools. This post goes into detail about how to think about a project’s CLI and implementing one using the Invoke Python package.

  • Code Size Optimization: GCC Compiler Flags

    by François Baldassari

    In this post, we will review compiler options that we can use to reduce firmware code size. We will focus on arm-none-eabi-gcc, the GCC compiler used for ARM-based microcontrollers, though most of the compile-time flags we will cover are available in other GCC flavors as well as in Clang.