BlueNRG-LP -first SoC with Bluetooth Low Energy supporting 128 connection simultaneously

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BlueNRG-LP from STMicroelectronics is the first Bluetooth Low Energy SoC to support 128 concurrent connections. The device received the Bluetooth Low Energy 5.2 certificate. Long range, 2Mbps transfers, and advertisement extension are just a few of the features of BlueNRG-LP. To achieve a high level of performance and optimization, STMicroelectronics focused on the radio chip and the microcontroller. The Cortex-M0 + MCU is installed, which runs at 64 MHz and uses 64 KB of RAM. For comparison, BlueNRG-1 and BlueNRG-2 are based on the Cortex-M0 core with a frequency of 32 MHz and 24 KB of RAM. For safety reasons, the new device also has a one-time programmable memory area.

New industrial and technological challenges

When choosing SoC Bluetooth, engineers pay attention to the latest trends that shape their industry. Industrial applications need to connect even more sensor nodes to the gateway. Audio processing capabilities are also gaining importance. A Bluetooth SoC is required to increase computing power while keeping material bills low and energy consumption low. Meeting these challenges is not easy and requires optimization both at the radio and microcontroller level. Simply connecting up to 128 devices simultaneously is unique in today’s world, but is it sufficient? We know engineers will ask two key questions: “How good is this SoC?” and “How does this chip benefit my design?” The answers are on how the BlueNRG-LP achieves more power, better safety, greater efficiency and lower costs.

Check if BlueNRG-LP is the solution for you - testing tools

Choosing a Bluetooth SoC is often a complicated task. Many factors affect your decision, ranging from cost to past experience, performance and ease of use. To facilitate this task and expedite the decision making process, STMicroelectronics has released software updates and development tools. Designers can use the STEVAL-IDB011V1 BlueNRG-LP evaluation board along with the BlueNRG Navigator software package. The collection includes demo programs to facilitate a quick start with the BlueNRG-LP system, both in testing and creating your own application.

The number of demos available on the BlueNRG Navigator interface is quite large. From around 20 applications, designers can quickly test the chip’s ability to connect to up to 128 devices. They can also try advertisement extensions, broadcasting up to eight channels instead of the traditional three. One “demo” project demonstrates the higher available bandwidth and the other shows the possibilities for greater coverage. It is a great convenience and help for designers.

The package also includes a new version of the BlueNRG power consumption tool. The tool offers a graphical representation of the low-power capabilities. Developers can also decide to test a new device by transferring code running on previous BlueNRG SoCs. Since it’s just a matter of transitioning from Cortex-M0 to Cortex-M0 +. The process is relatively straightforward.

High data transmission speed

Industrial application teams have to deal with significant limitations that affect the range or speed of data transmission. This demand is especially important in industrial applications. An example is a gate that connects to countless boards throughout a smart factory.

On the other hand, other devices need to transfer large amounts of data quickly, for example when updating firmware. The new SoC from STMicroelectronics meets both of these requirements. By offering LE 2M PHY, BlueNRG-LP can achieve data transfer rates of up to 2 Mbps. For comparison, the LE 1M PHY in the previous SoC BlueNRG stopped at 1 Mbps.

Long range mode

BlueNRG-LP offers LE Coded PHY, allowing Bluetooth devices to be placed at much greater distances without the need for an additional power amplifier. ST testing using existing development boards and applications has achieved a distance of 1.3 km (0.8 mile).

Increasing the range is possible because LE Coded PHY uses Forward Error Correction, which adds extra bits to each packet. However, the data redundancy leads to a lower throughput of 125 kbps. Another feature that helps to avoid interference is the channel # 2 selection algorithm (CSA # 2). While CSA # 1 can only hop between 37 channels, CSA # 2 has 65,535 channels at its disposal. This large selection helps you avoid collisions. Whether there are multiple devices nearby or long distances between them, CSA # 2 increases network reliability.

Link budget

Engineers working on Bluetooth applications always conduct a link budget analysis. The analysis is a design aid that helps them predict overall performance. It gives designers the ability to predict specific problems, such as insufficient signal strength.

BlueNRG-LP has a link budget of 112 dB and 105 dB and it is the largest link budget among similar systems on the market. As a result, engineers can predict better performance with the same power consumption compared to devices with a lower link budget.

Security - a key feature of application

Security is another key aspect that engineers focus on when designing a system. Consumers are much more sensitive to privacy and security issues. As a result, teams looking to build a Bluetooth system pay attention to features that protect users and data. BlueNRG-LP provides answers to these critical engineering challenges. One is the presence of a secure bootloader that checks the signature of the firmware before it boots. Such a measure protects against rootkits or low-level attacks. Developers can also disable SWD and UART access to protect Flash. Likewise, 1 KB of OTP memory is programmable once to guarantee its integrity. Therefore, a hacker with access to the device would not be able to clone or modify its contents.

More computing throughput and lower power consumption

The designers goal is to find a way to improve performance, accuracy and comfort of use. To solve this challenge, engineers often turn to a device with higher computing performance and low power consumption at the same time to preserve battery life.

BlueNRG-LP offers a new solution to this challenge. With a higher frequency and more powerful architecture, the SoC can now handle more complex algorithms. Applications using MEMS and voice libraries are gaining more and more popularity in embedded systems. In addition, ST also provides a free Bluetooth-SIG certified MESH stack. As a result, it is very easy to cover large areas of up to 32,000 nodes.

Despite the higher frequency and more memory, BlueNRG-LP also consumes less energy. Its peak transmission current is 4.3 mA (0 dBm), while the BlueNRG-2 needs 8.3 mA (-2 dBm). Improving energy consumption is also significant when idle. BlueNRG-LP only needs 0.6 µA in DEEPSTOP mode with RAM backup.

The exact price

Low unit price is crucial. To meet this challenge and keep BlueNRG-LP profitable, STMicroelectronics has equipped the SoC with 256 KB of Flash memory. The Bluetooth stack of this device is typically 80KB to 100KB. Thus, developers have around 120KB for their application, which in most cases is sufficient.

The manufacturer optimized the pricing structure by offering three types of packages. QFN32 has 20 GPIOs, while QFN48 and WLCSP49 have 32 and 26 respectively. In addition, BlueNRG-LP variants with half the RAM are also offered. Therefore, teams that only need 32 KB and fewer pins don’t have to pay for more. There are also models that can reach temperatures up to 85 degrees C and 105 degrees C. The latter will be suitable for industrial applications, while others will choose the former and thus save.