“Bluetooth® connects us to the world through smartphones. We can interface with door locks, thermostats and even our cars. But are all Bluetooth the same? Do you use Bluetooth for streaming music from your phone to a smart speaker to unlock your car?
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Bluetooth® connects us to the world through smartphones. We can interface with door locks, thermostats and even our cars. But are all Bluetooth the same? Do you use Bluetooth for streaming music from your phone to a smart speaker to unlock your car?
The answer is “yes” or “no”. Bluetooth® Low Energy is a standards-based protocol that enables interoperability between different devices and products. Of course, there are optional additional functions to expand the functionality of more complex solutions. When choosing the right Bluetooth solution for your application, you should consider the following three basic aspects: software capabilities, hardware, and cost.
Software function
There are two important technical details to consider in terms of software:
・ Which core specification can the device be certified?
・ What feature set does the device support?
The core specification defines the basic functions of Bluetooth® Low Energy. These features must work to create an interoperability experience for consumers when their phones interact with products made by hundreds of different companies. These functions are necessary for the release of BTX.X certified products (such as BT5.0). Other features related to different Bluetooth® low energy specification versions (outside of the core specification) are optional. For example, BT5.0 adds high-speed mode, remote mode and extended advertising, but your application does not need to support these functions to obtain BT5.0 certification. Similarly, BT5.1 adds the directional function as an additional function.
hardware
The hardware that runs the Bluetooth protocol stack is also very different. Some basic devices have a single core that can be used for both application and RF functions, while integrated devices provide the application core and microcontroller (MCU) core respectively. In addition, one-time programmable devices are based on read-only memory and cannot be updated after programming, while flash-based devices can be upgraded thousands of times, and can even be upgraded wirelessly in the field.
If you aim to design a scalable and reliable application, it is important to evaluate cost-effective, high-quality devices with various hardware options including integrated application MCUs and flash memory architectures. This type of evaluation allows you to choose the right features at the right price.
The following table shows some of the key features of Bluetooth Low Energy devices in TI’s product portfolio.
|
CC2640R2L |
CC2640R2F-Q1 |
CC2642R-Q1 |
CC2652RB |
CC2652P |
|
|
Most cost-effective |
The smallest size and lowest power automotive option |
Complete BT5.1 feature set, car options |
No external crystal needed-smallest system size |
Longest distance, highest output power, multi-protocol Bluetooth® low energy |
|
|
unit price |
$0.85 |
$1.44 |
$1.86 |
$3.00 |
$3.10 |
|
Bluetooth Core Specification|Bluetooth Feature Set |
BT5.1 | BT4.2* |
BT5.1 | BT4.2* |
BT5.1 | BT5.1 |
BT5.1 | BT5.1 |
BT5.1 | BT5.1 |
|
Smallest package option |
5mmx5mm Quad Flat Lead-Free (QFN) Package |
2.7mm x 2.7mm Wafer Chip Scale Package (WCSP) |
7mm x 7mmQFN |
7mm x 7mmQFN |
7mm x 7mmQFN |
|
Application MCU core |
M3 |
M3 |
M4F |
M4F |
M4F |
|
Flash memory (KB) |
128 |
128 |
352 |
352 |
352 |
|
Maximum output power |
+5 dBm |
+5 dBm |
+5 dBm |
+5 dBm |
+20 dBm |
|
Protocol support |
Bluetooth® Low Energy, proprietary 2.4 GHz |
Bluetooth Low Energy® |
Bluetooth Low Energy® |
Bluetooth Low Energy® + 802.15.4 (Zigbee, Thread) |
Bluetooth Low Energy® + 802.15.4 (Zigbee, Thread) |
*Some restricted options apply to BT5.0
Table 1: SimpleLink™ low energy Bluetooth® combination products and specifications
Certain applications, such as wearable devices, need to be as small as possible to avoid intrusion. Other applications require higher performance, such as longer distances or multi-protocol operation, and are not sensitive to size. TI’s product portfolio provides hardware options that can be expanded between memory footprint, performance, Bluetooth capabilities, and packaging. For example, the smallest size product uses the CC2640R2F-Q1 in a 2.7mm x 2.7mm WCSP package. The most cost-effective product is the CC2640R2L in a 5mm x 5mm QFN package. In order to achieve multi-protocol support and long-distance transmission, the best choice is CC2652P and its integrated power amplifier.
cost
When designing low energy Bluetooth® products, choosing the right features and considering the price are equally important. The devices in the SimpleLink product portfolio have a variety of price, feature, and performance options. The latest device in TI’s Bluetooth platform, CC2640R2L, is a flash-based Bluetooth wireless system-on-chip with a starting price of US$0.85. In addition, CC2652RB can save system costs by eliminating the need for external crystal oscillators. It integrates this key system component into the package of the device. Compared with crystal-based solutions, the entire system saves an average of US$0.10 to US$0.20.
Remember-all Bluetooth is standard, but not exactly the same. When designing an application, it is very important to cover the basic elements of Bluetooth (software functions, hardware, and cost) so that you can find the right solution whether you want to unlock the car or set the indoor temperature. TI’s product portfolio covers all foundations by providing various software options (BT5.0, positioning, coexistence) and hardware options (memory, packaging, performance).
