On a weekly basis, I receive a fair number of emails with questions about how to design embedded systems. One question that seems to be asked more frequently than others is how to write a configurable driver that uses callbacks with interrupts. If a developer is writing a driver that will be reused in multiple … Continue reading Using Callbacks with Interrupts
Category: C Concepts
5 Techniques to Delay Code Execution
An interesting problem that often comes up in embedded software implementation is figuring out how to delay code execution. Sometimes a developer might just want there to be a 10-microsecond delay to allow an I/O line to stabilize before reading it or may want a specified time period between reads to debounce it. In this … Continue reading 5 Techniques to Delay Code Execution
7 Steps to Create a Stack Monitor
One of the most painstaking bugs to hunt down in an embedded system is when the stack overflows its boundaries and starts to overwrite memory regions that are nearby. The symptoms of stack overflow usually appear randomly when just the perfect storm of interrupts and function calls are occurring which leads them to be difficult … Continue reading 7 Steps to Create a Stack Monitor
7 Steps to Create a Reusable Debounce Algorithm
A quick google search reveals that there are over 212,000 websites that examine how to debounce a button. After examining a number of them it is obvious that these implementations are not meant for reuse. The implementations and strategies often lack scalability, the ability to debounce multiple buttons easily and portability. They are tightly coupled … Continue reading 7 Steps to Create a Reusable Debounce Algorithm
Using strstr to Parse JSON Messages
When I first started to write embedded applications in C, microcontrollers were not very powerful, and we rarely ever parsed or worked with human readable text. Instead, we often generated packetized data where each byte in the message represented some specific type of information that we would then quickly decode on the fly as it … Continue reading Using strstr to Parse JSON Messages
10 Pain-free Steps to Configure an Interrupt Controller
Properly setting up interrupts on a microcontroller isn’t easy. The number of times an engineer has setup interrupts in their career doesn’t seem to make a difference. Configuring interrupts always has some gotcha hidden away that leaves the developer scratching their head and seeking answers in an obscure data sheet or online code snippet. Thankfully … Continue reading 10 Pain-free Steps to Configure an Interrupt Controller
5 Tips for Getting Started with Digital Signal Processing (DSP) on Arm Cortex®-M CPUs
Digital signal processing (DSP) provides developers with the ability to clean-up and analyze complex signals in a flexible and cost-efficient manner all from software. When developers typically think about DSP, they often picture expensive, dedicated processors, but modern microcontrollers, such as the Arm Cortex-M processors, now include DSP extensions that allow DSP algorithms to be … Continue reading 5 Tips for Getting Started with Digital Signal Processing (DSP) on Arm Cortex®-M CPUs
The Hardware Abstraction Layer Design Process
Using a HAL is a great way to develop software that can be easily reused and ported from one application and platform to the next. Why would a developer want to do such a thing? For starters, reinventing the wheel over and over again gets pretty boring. I believe most developers want to be working … Continue reading The Hardware Abstraction Layer Design Process
7 Tips for using assertions in C
One of the greatest bug squashing tools available to embedded software developers is the assert macro. Despite the power of assert, I rarely see it implemented and in the cases where it is used the implementation is either flawed or incorrect. The following seven tips should help elucidate not only when and where to use … Continue reading 7 Tips for using assertions in C
The Biggest Embedded Software Issue Is …
There are many different problems and challenges that embedded software developers are facing today. One of the biggest, and least spoken about issues that I have encountered is that developers are writing their software for success. Writing for success sounds great, except that what I mean is that developers are writing their software assuming that … Continue reading The Biggest Embedded Software Issue Is …