When it comes to low-energy short-range communication, Bluetooth LE often stands above the rest (especially for battery-powered devices such as in-ear headphones, doorbells, and sensors). While there are many Bluetooth development platforms around, they are often not suited for dedicated Bluetooth Audio projects as they either lack audio amplifiers, audio jacks, or software examples specifically for audio. In this Maker Board Spotlight article, we will look at the Nordic Semiconductor nRF5340 Audio DK to see its specifications, what it can be used for, and why you should get one for your next Bluetooth audio project!
What’s included in the nRF5340 Audio DK?
The Nordic nRF5340 Audio DK is a complete development board and complement software development environment that integrates all the hardware needed to create advanced Bluetooth audio projects while simultaneously introducing the nRF5340 SoC and the nPM1100 power management IC.
The nRF5340 is a powerful Bluetooth SoC that integrates a multicore architecture that helps to improve code efficiency while allowing for advanced power-down features (i.e. cores can be switched off as needed). The nPM1100 power management IC provides the development kit with a high-efficiency buck converter as well as battery management and charging with a charge current of up to 400mA.
The small form factor of both the nRF5340 and nPM1100 allows for use in even the smallest Bluetooth devices (such as in-ear headphones), but for development purposes, the nRF5340 Audio DK integrates these chips onto an easy-to-use board with various pin headers, sockets, and connectors. To aid development in Bluetooth audio projects, the nRF5340 integrates two 3.5mm audio jacks with one being used with headphones and the other for microphones.
For additional hardware programmability, the nRF5340 Audio DK also has onboard LEDs and buttons for quick device development while an array of Arduino Shield headers allow for use with pre-existing Arduino shields.
Nordic nRF5340 Audio DK Specifications
The nRF5340 SoC that powered the development board is a two-core ARM CPU with one core being a network processor and the other an application processor. While both cores can be used to execute arbitrary code, the goal of the network core (which is a lightweight processor) is to offload complex network routines from the Application core (the heavy-hitting processor).
As such, applications can continue to run while the network core deals with reconnections, message queues, and protocols. The network core is a 64MHz ARM Cortex-M33 that has 256KB of flash and 64KB RAM while the application core is a 128MHz ARM Cortex-M33 processor with 1MB flash and 512KB RAM. Additionally, each core supports ARM TrustZone to ensure firmware integrity from injected malware, something that is becoming increasingly important in modern devices.
The nRF5340 SoC also integrates a range of different peripherals for interfacing with other devices including UART, full-speed USB, QSPI, SPI, PWM, QDEC, and I2S. With regards to circuit I/O, the nRF5340 SoC integrates a 12-bit 200kbps ADC, GPIO, 5 user-programmable LEDs, 4 user-programmable LEDs, and two 3.5mm audio jacks for audio input and output.
Furthermore, the nRF5340 Audio DK also incorporates an SD card reader for data logging, a Cirrus Logic Audio DSP CS47L63, NFC, and SEGGER J-Link debugger which removes the need for any additional programmers while providing full debugging capabilities (live memory view, program stepping, and variable injection).
What can you do with the nRF5340 Audio DK?
One of the most obvious uses for the nRF5340 Audio DK is to develop Bluetooth audio projects that have low-energy requirements. The nPM1100 PMIC also makes the development board geared towards battery-operated projects such as wireless headphones. If combined with the Nordic Power Profiler Kit 2, the power consumption of the nRF5340 can be logged in great detail while also allowing for low-energy mode testing to make an accurate estimate of battery life.
Additionally, the nRF5340 Audio DK is also great for prototyping home automation devices including wireless sensors, actuators, and command units. The ability to operate with a speaker and microphone allows for the nRF5340 Audio DK to listen to voice commands, and the use of low-energy modes can allow for the device to wake up on detecting sound thus saving energy when not in use.
Even though the nRF5340 Audio DK is designed for Bluetooth audio projects, it can still be used as a generic nRF5340 platform. This allows for the creation of any wireless Bluetooth project whether it is a wearable device, a remote IoT sensor, or even replacing an Arduino.
Who should buy the Nordic nRF5340 Audio DK?
If you are looking to create an advanced project that needs low-energy requirements and/or Bluetooth capability, then the nRF5340 Audio DK could be the ideal choice for you. The large number of GPIO connections combined with the various peripherals allows the nRF5340 Audio DK to be integrated into a large number of projects while the onboard SEGGER J-Link allows for programmability no matter where it is installed.
However, it should be noted that while the nRF5340 Audio DK is a powerful development board, it is also significantly more advanced than Arduino dev kits, and as such is not suitable for beginners. The Nordic Connect SDK includes a wide range of examples while aiding in the installation of SDKs and IDEs, but the examples are geared towards commercial-grade products meaning that they can be extremely large in size (requiring safety measures, error reporting, and alternative hardware initialization should something fail during start-up).
Of course, don’t let this scare you, the Nordic DevAcademy has excellent guides on programming the nRF5340 as well as using various peripherals. These guides and examples are also simpler to follow compared to the examples that come with the SDK, and the documentation goes over every line of code and why it’s needed.
Furthermore, the nRF5340 is not compatible with the Arduino IDE (unlike other Nordic products that are), and this means that you are limited to libraries provided by Nordic. But, if you are looking to create advanced Bluetooth projects that have the possibility of becoming commercial products then the nRF5340 Audio DK is an extremely powerful platform to prototype on.
Final Thoughts on the nRF5340 Audio DK
The nRF5340 Audio DK is an extremely powerful development board that provides many functions and peripherals. The integrated USB programmer makes communication with the development kit extremely easy, and the Connect SDK application helps to accelerate the installation of SDKs and tools needed to work with the board. The low energy nature of the nRF5340 combined with the nPM1100 PMIC allows for the development of devices that can last for long periods of time on battery power, and the Bluetooth capabilities combined with the audio hardware allow for the creation of almost any wireless Bluetooth audio project.