Hardware (Systems-on-Chip (SoCs)) and firmware (RF protocol software) form a platform for complex Bluetooth Low Energy (Bluetooth LE) applications. But a discrete Bluetooth LE SoC and "stack" is of little practical use on its own. Some development work is required to come up with a working prototype. The good news is that one of Nordic’s key strategies is to make this development process as simple as possible such that everyone from makers and hobbyists through to highly-experienced engineers can design wirelessly-connected products.
There’s no need to embark on time-consuming and difficult hardware prototyping to start developing a Bluetooth LE product; Nordic supplies fully- operational hardware in the form of the nRF52 Development Kit (DK). The kit can be connected to a PC or Mac and forms all the hardware for designing with the nRF52832 and nRF52810 SoCs. (There’s a separate DK for the high-end nRF52840 chip.)
The DK provides simple access to all the SoC’s I/Os and interfaces via connectors and includes four user programmable-LEDs and -buttons. Another handy feature is that the DK is hardware- compatible with the Arduino Uno (Revision 3) standard, enabling the use of any of the many commercially available third-party shields to enhance functionality.
The DK’s Bluetooth LE SoC is blank on delivery. The developer is thus free to choose the best SoftDevice (Nordic’s RF protocol software) for their project. The preferred SoftDevice can be downloaded from Nordic’s website as a precompiled binary file and seamlessly ported to the DK’s SoC using nRF Connect, a cross-platform tool from Nordic that enables testing and development with Bluetooth LE. nRF Connect comes in desktop and mobile versions which allow the developer to use Bluetooth LE connectivity to communicate with their prototype from a PC or smartphone respectively.
Creating application code
Application software development — whereby the engineer writes his or her own code to optimize the functionality of the wireless product for a particular application, for example a heart rate monitor — requires three essential components. The first is an integrated development environment (IDE) with a Nordic-supported compiler, second is Nordic’s nRF5 Software DK (SDK), and third is the company’s nRF5x Command Line Tools.
There are four IDEs that can do the job: SEGGER Embedded Studio, MDK-ARM Keil, GNU/GCC, and IAR (all these IDEs support Windows, but only SEGGER and GNU/GCC also support Linux and OSX). The nRF5 SDK contains application examples, source files, and other useful development items. (There are also specialized SDKs that add to the generic SDK and extend functionality to things like mesh networking and wireless charging.) The nRF5x Command Line Tools allow the developer to do extra tasks like program Nordic SoCs with things like SEGGER J-Link programmers and debuggers or combine up to three HEX files into a single file.
The IDE supports all the development activity while the Nordic SDK and Command Line Tools specifically support application coding for Nordic chips. The IDE then looks after application code compilation for porting straight to the Nordic SoC. (Nordic’s unique software architecture means that during application development the SoftDevice remains untouched and the critical dependencies for efficient and reliable stack operation are maintained.)
The programmed DK can then be used to check out the functionality of the design (by, for example, wirelessly sending data from a sensor connected to the DK to a smartphone or other nRF52 DK). The developer can then use the development tools to easily debug his or her code, add more functionality, and optimize its performance.
Nordic’s development tools make it easier than ever to prototype a wireless product. But as with all engineering design, things can sometimes get challenging, particularly for the inexperienced. The good news is that someone has typically been down the path before and has shared the experience on Nordic’s DevZone. If that’s not the case, the developer can ask for help and one of a community of over 25,000 fellow designers will soon come up with the answer.