Overview: The article introduces USB technology, its evolution, and its significance in modern electronics. It explores the nRF52840 Dongle, its USB connectivity, key features, and applications in wireless communication projects.

USB or universal serial bus is a physical device constructed and operated following universally accepted standards and is more commonly used for networking and charging purposes. It is the most often utilized port facilitating communication and power supply between peripherals and computers.

What are the key advantages of USB technologies?

They are hot-swappable devices that can be connected or disconnected without powering down the computer. It has the ability to connect various devices, including keyboards, mice, external drives, printers, scanners, flash drives, and more. It makes connections easier and standard, allowing for quicker transmission rates. They are generally considered self-configurable because they can automatically configure themselves when connected to a host system.

Evolution of USB Technology

Since its introduction in 1996, USB technology has evolved a lot. It has progressed from an initial 1.5 Mbps transfer speed to the current USB 4 standard capable of 40 Gbps. 

With each new version—USB 1.1 (12 Mbps), USB 2.0 (480 Mbps), USB 3.0 (5 Gbps), USB 3.1 (10 Gbps), and USB 3.2 (20 Gbps)—the technology has constantly improved its ability to send data and power, reflecting significant advancements in digital connectivity standards. The latest iteration, USB 4, introduced in 2019, utilizes the USB-C connector, offering improved performance while maintaining compatibility with earlier USB devices. 

What are USB dongles?

USB dongles are compact devices that connect to a USB port on a computer or other electronic devices, serving various functions such as providing wireless connectivity, data transfer, or additional features. The proliferation of wireless communication is made possible by low-power integrated circuits in these portable devices, as shown in Fig. 1.

Fig. 1 AT88CK590 USB DONGLE Source: oemsecrets

USB dongles, particularly 3G and 4G models, connect to computers and other electronic devices via USB ports. The term "dongle" is now commonly used to refer to a broadband wireless adapter that can connect to wireless networks and transfer data. 

Key Features

These dongles often resemble standard USB flash drives but with added functionalities to meet modern connectivity needs. Most USB dongles include flash memory that can function as a storage device. This memory often contains a file system with software necessary for the dongle's operation, including drivers for various operating systems and applications for managing the connection.

3G/4G USB dongles serve as modems that allow users to connect to cellular networks for internet access. These devices typically contain a small modem and transceiver, enabling them to communicate with 3G or 4G networks. When plugged into a laptop or desktop computer, the operating system can automatically recognize the dongle and load the necessary drivers and management software stored within its flash memory.

Their plug-and-play functionality is the most advantageous feature. After plugging it into a USB port, the operating system often detects the device and configures it automatically, simplifying the setup process.

USB dongles are in high demand for applications in WLAN, Bluetooth, and LTE. They are employed to transmit and receive signals between devices. These antennas should be compact in size, capable of operating on dual and/or multiple bands, and possess an adequate bandwidth within each band. These antennas have been proposed in a wide range of shapes and operating principles.

A USB Dongle To Consider: nRF52840 Dongle

The nRF52840 Dongle, as shown in Fig. 2, is a versatile USB stick-like PCB that houses the nRF52840 chip. It is a cost-effective USB dongle supporting all Nordic semiconductor development tools. 

Fig. 2 nRF52840-Dongle by Nordic Semiconductor Source: oemsecrets

The dongle has the ability to support multiple wireless protocols simultaneously, including Bluetooth Low Energy (BLE), Bluetooth mesh, Thread, and Zigbee, providing significant operational flexibility. By enabling Bluetooth 5.2 and IEEE 802.15.4 compatibility, developers can create solutions that integrate different communication standards. This multiprotocol support is particularly valuable in complex IoT applications where device interactions are essential.

The support for Arm Cortex-M4 enhances computational performance with low power consumption. The floating-point unit efficiently handles complex mathematical operations, which is particularly beneficial in applications requiring real-time signal processing. With its DSP instruction set, the Cortex-M4 can perform operations like filtering and FFT (Fast Fourier Transform) more rapidly than general-purpose processors.

The dongle works seamlessly with the nRF Connect for Desktop application, which provides a user-friendly interface for developing wireless applications.

The dongle includes programmable buttons and LEDs, enabling developers to create interactive applications that provide real-time feedback during testing and development.

It comes with a 2.4 GHz chip antenna for reliable wireless communication. The embedded Arm CryptoCell CC310 ensures security mechanisms, making the dongle ideal for applications requiring high-performance computing and advanced cryptographic operations. With 15 GPIO pins and direct USB interface connectivity, the dongle provides extensive flexibility for developing custom hardware interfaces.

The ability to operate within a broad voltage range allows the dongle to be powered directly from various sources, including USB ports (which typically provide 5 V) and lower-voltage battery systems (such as 1.8 V lithium batteries). This flexibility makes it suitable for a wide range of applications.

It serves as an ideal development platform for advanced wearables, IoT devices, and interactive entertainment systems like gaming controllers and VR applications. With its support for Bluetooth 5.2, the dongle offers enhanced range and data rates, making it suitable for connected home sensors and industrial IoT solutions.

Summarizing the Key Points

  • USB dongles are versatile devices that connect to USB ports, providing wireless connectivity, data transfer, and additional functionalities, making them essential for modern electronics.
  • With plug-and-play functionality, USB dongles automatically configure when connected, simplifying setup processes and enhancing user experience across various devices and operating systems.
  • The nRF52840 Dongle supports multiple wireless protocols, including Bluetooth Low Energy and IEEE 802.15.4, enabling developers to create flexible solutions for complex IoT applications.

Reference

Chiang, W., Ku, C., Chen, C., Wang, L., Abu, P. a. R., Rao, P., Liu, C., Liao, C., & Chen, S. (2019). A Power-Efficient multiband Planar USB dongle antenna for wireless sensor networks. Sensors, 19(11), 2568. https://doi.org/10.3390/s19112568

Elghannai, E., & Rojas, R. (2014). Design of USB dongle antenna for WLAN applications using theory of characteristic modes. Electronics Letters, 50(4), 249–251.
https://doi.org/10.1049/el.2013.3929

LIU ENFEI-KTH ROYAL INSTITUTE OF TECHNOLOGY - USB dongles for mobile broadband

Oemsecrets - nRF52840-Dongle by Nordic Semiconductor