I had a few of PCBs left over from the V3 MetaClockClock, and originally I planned to finish a build with them by the end of 2020. But as always: things took a bit longer than expected, so I finally finished it today on the first day of the year 2021.
The build uses the same hardware as in the previous V3, but instead of an ‘artistic’ canvas background I decided for a more natural and wood design:
The Eclipse CODAN (Code Analysis) plugin is part of CDT and is a powerful static analysis tool finding all kind of possible bugs and issues. Still to my surprise not many C/C++ developers take advantage of it maybe because they are not aware that it exists?
ups! Programming error detected by CODAN
In this article I show a few tips how to effectively use it, especially with the NXP MCUXpresso SDK.
The NXP Kinetis devices implement a UID (Unique ID) for each device, using the ‘Unique Identification Register) which is part of the SIM (System Integration Module):
SIM Unique ID (NXP K22P144M120SF5RM.pdf Reference Manual)
While this number should be unique, I was wondering last week why students in the labs reported the same UID for multiple robots in the lab. So maybe this number is not so unique as it should be? Continue reading →
Having visibility and insights into a running system is highly valuable or critical: not only for optimizations but as well to verify the system design and behavior. In Getting Started with Microsoft Azure RTOS (aka ThreadX) I showed how to quickly run Azure RTOS. This article is about getting trace out of an ThreadX application and show it in TraceX.
Reentrancy is an attribute of a piece of code and basically means it can re-entered by another execution flow, for example by an interrupt or by another task or thread. This is an important concept and still a lot of code ‘in the wild’ does violate reentrancy. As a result the application crashes immediately in the best case. Worse it crashes randomly or even worse it behaves incorrectly 😦 .
Reentrancy is always a concern if using standard library functions, including printf() or malloc(). FreeRTOS offers a reentrant wrapper to the standard malloc() and free() (Memory Scheme 3)
If you are a regular reader of my articles, you probably know that I’m using FreeRTOS in most of my applications, for obvious reasons. But clearly this is not the only RTOS out there. After Microsoft had acquired Express Logic back in April 2019 things kept quite for a while. To me the crown jewel of Express Logic is the ThreadX RTOS. But recently Microsoft is pushing more and more the ‘Azure Sphere’ and trying to monetize the ‘IoT’ (I apologize for mentioning that overused acronym) application space and providing it now free for devices from selected partners which includes NXP now.
Philips Hue Smart LED stripes are great, but they have a disadvantage: the LED density is rather low: one LED cluster (WW, RGB, CW) every 55 mm. This leads to the problem that individual dots might be visible if the LED stripe is directly visible. Even if the LED stripe is used for indirect ambient light it means that individual dots might still be visible on the wall or ceiling. The solution is to create a ‘high density’ Hue smart LED stripe: