Martin Cowen ⁽⁴⁵⁾

If you are developing a BLE application with Nordic Semi's SDK, there is a need to generate a UUID for your custom services and characteristics, for example, NovelBits MIDI example. Mohammad Afaneh gives the rules for these UUIDs and suggests using a general purpose UUID generator followed by a manual check for clashes with the BT SIG reserved range. The Nordic SDK method of declaring these UUIDs requires them to be given as byte arrays in reverse order, with least significant byte first. Although this is not difficult to do manually, there is some possibility of error which would be difficult to detect without going through the full debug cycle of programming a device and reading back the UUIDs on a tool such as LightBlue or nRF Connect. I have automated the whole process in a simple Windows Form app - BLE UUID Generator The program generates a UUID immediately when opened, using the built-in Windows GUID functionality. This is checked for collision with the BT SIG reserved range XXXXXXXX-0000-1000-8000-00805F9B34FB and then displayed in the text box as a snippet of C code - as a comment and as a reversed order byte array as required by the Nordic SDK. It…

I was getting a little frustrated with the Nordic examples and tutorials all being not quite ready for use. Not as badly frustrated as this guy but there always seemed to be some mismatch between what was required and what I was using, even when I chose the preferred tools. OK, I made a mistake assuming that I should start with the nRF51-DK because that is a smaller, simpler, cheaper chip. Although when you look into pricing, you find that nRF51's are not necessarily cheaper So I got myself onto the nRF52-DK so that I could use the latest SDK 16 and the Segger SES toolchain, which meets all the requirements in the Getting Starting guide. After going through that, I wanted to find a tutorial that was written from outside Nordic Semi so that it could be more objective about the tools. Given that Mohammad Afaneh is presenting these Ellisys BT videos he seems to be an independent (of Nordic) expert, so his post on How to build the simplest nRF52 BLE Peripheral application (Lightbulb use case) seemed to be a good fit with what I wanted to learn and how to learn it. The rest of this post is my attempt to…

Apple have just announced their latest 4.7" iPhone. Confusingly they are calling it the iPhone SE, even though they already had an iPhone SE which was a 4" screen. I'm looking at it as an upgrade to the iPhone 6s 128 GB from September 2015, so the comparison only covers that screen size. Most of the data in this chart is from Apple's comparison page. CPU and battery specs are from the relevant Wikipedia pages. The historical UK pricing at launch was obtained from the Guardian. DXO Mark and Geekbench scores are from their own sites. Bold text is used for improvements. Since the iPhone 8 did not launch with a 128 GB option, the choice would have been the 256 GB option at £849 so the iPhone SE (2nd gen) at 128GB at £469 looks like a good deal. Added confirmed DXOMark, RAM and CPU for SE (2nd). Added iPhone 12 mini

While learning about RTOSes, I came across the idea of Timer Coalescing which improves performance by eliminating unnecessary context switches. But there is no reason that this technique cannot be applied to bare metal firmware (without RTOS). To test out how well it works, I implemented it using a STM32F4 discovery board. I wanted to see the improvement factor in a typical use case, so I decided on running 8 software timers on a 1ms timer peripheral. The software timers count down to 0 then reload themselves. From previous experience, typical periods were chosen for these timers of 1000, 200, 125, 50, 18, 27, 40 and 600ms. (If they had a common factor of say 5ms, then it would make more sense to use that as the peripheral timer rate, but it restricts the flexibility for future changes.) TIM6 was chosen because we only need a Basic 16 bit timer in the STM32F4 architecture. It runs off APB1 at 42 MHz (HCLK at 168 MHz). Prescaler was set to 41, Counter Period ARR set to 1999 for 1ms and auto-reload preload set to Disable. TIM6 interrupts were enabled. Once all this is set up in the Device Configuration Tool, all…

Knowing what kind of project you are working on can help you work out which planning method and software methodology to apply, as well as what management strategy to use. Once you have categorised your project into one of these four types, you will improve your expectations about the timescale and velocity. Not knowing about these project types leads to confusion about the project direction and pace, which can be demoralising for staff and leads to misunderstanding by customers, management and other departments. The trend in the last 20 years has been to apply Agile methodologies to all projects, but this Feabhas video explains why that isn't always a good idea. (The click-baity title isn't what it first appears). I'd like to expand on the video by looking at the relationship between these four project types and the appropriate planning and execution strategies. These four project types were described by Eddie Obeng, who said "As a project manager, as a business, we have to understand the type of project that we are working on because each type of project has a different management strategy associated with it. More specifically, we have to apply our effort in different places and in different ways…