How to Simplify Effective Bluetooth® Implementations in Smart, Low-Power
Applications
By Toshiba Electronics Europe
Summary
Low-Energy (LE) technology in the latest Bluetooth® 4.0 standard is providing an effective
platform for a new generation of smart, networked applications. Smart metering, personal
wellness and sport monitoring, home automation and other emerging applications can all
benefit from Bluetoothʼs ability to exchange or collect information from a variety of sources
for control, sensing and measurement purposes. This paper looks at the background to the
technology and describes an implementation that simplifies the adoption of Bluetooth in a
wide range of embedded applications.
Introduction: Building on Bluetooth®
Since the Bluetooth standard was first published, Bluetooth Special Interest Group (SIG)
members and developer communities have been quietly filling consumersʼ lives with shortrange wirelessly-connectable products such as mobile phones, headsets and PC dongles.
According to InStat Research, more than two billion Bluetooth-enabled devices will ship in
2013.
As the middle member of a “holy trinity” of industry standards for wireless communication,
sitting between ZigBee® low data-rate wireless aimed at applications such as mesh
networking and multi-gigabit Wi-Fi™ (IEEE 802.11x) targeting WLAN and Internet
connectivity, Bluetooth (which supports data rates up to 2.1Mbit/s) offers advantages such
as low design risks for product developers, fast time to market, access to a large pool of
developer skills, and certified interoperability scheme with certified compliant devices from
other manufacturers. Interoperability enhances the marketability of Bluetooth devices,
encourages development of new and innovative products and applications, provides
flexibility for end users to mix and match products from various manufacturers, and ultimately
serves the Bluetooth SIGʼs vision of enabling seamless ad-hoc connectivity.
Bluetooth has become a key factor driving almost universal consumer awareness of and
demand for wireless connectivity between personal and mobile devices. If the initial “killer
app” was the mobile phone headset, aided by widespread legislation to prevent drivers using
handheld mobiles, the subsequent growth of phenomena such as social media, smart
metering, personal wellness and sport monitoring, and home automation present a diverse
and growing range of further opportunities for Bluetooth as a ubiquitous, low-cost, ad hoc
wireless networking technology.
The World Moves On
These and other emerging applications could benefit from Bluetoothʼs ability to exchange or
collect information from a variety of sources for control, sensing and measurement purposes.
However, the legacy Bluetooth 2.0 and 3.0 standards are not well suited to ultra low-power
applications such as use in tiny sensors that may need to operate from a small power source
such as a button cell for periods sometimes as long as several years without requiring
replacement of the cell.
To encourage selection of Bluetooth as the standard of choice for these applications, the
Bluetooth SIG adopted the Bluetooth 4.0 standard in 2010. An important aspect of the latest
update is the addition of low-energy technology to the Bluetooth core specification. Bluetooth
Low-Energy (LE) enhances scope to take advantage of established Bluetooth performance
benefits in low-power battery-operated sensing applications.
Bluetooth LE significantly reduces peak, average and idle-mode power consumption, using
techniques such as speeding up connection and disconnection processes, thereby enabling
a lower total energy budget for the application. Figure 1 compares the time to execute
corresponding processes in standard Bluetooth BR/EDR protocols and Bluetooth LE,
showing that Bluetooth LE can be more than ten times faster from connection setup to data
transfer.
Figure 1. Speeding up connection/disconnection processes.
Bluetooth LE Applications
With this LE technology, the Bluetooth SIG is expecting the first new product introductions to
be focused on healthcare and fitness products. This vision encompasses devices such as
heart-rate monitors, watches, foot pods, GPS locators and pedometers that will enable
sports people to collect more accurate performance data. These, as well as medical devices
such as stethoscopes, glucose meters and pulse oximeters, will deliver advantages such as
more flexible, un-tethered use. Many will leverage Bluetooth connectivity in devices such as
PCs and mobile phones to permit easy wireless syncing, enabling data to be collected,
processed, analysed and shared easily and simply. The first Bluetooth 4.0 enabled medical
and fitness products reached the store-shelves in 2011.
Many other applications are being considered or evaluated, such as a promising Bluetoothbased traffic detection system trial in Houston. Using low-power Bluetooth-enabled sensors
positioned at the roadside in busy districts of the city, the pilot scheme tracks anonymous
MAC addresses of Bluetooth devices in passing vehicles as they progress through the cityʼs
traffic. This enables traffic conditions to be assessed accurately in real time without the huge
expense of automatic vehicle recognition technologies, such as visual number plate
recognition. Bluetooth LE operation is a key enabler of the system, as it permits small,
battery-powered nodes positioned at the roadside to collect the information needed to
monitor traffic movements. This saves the expense of providing wired connections to each
node, thereby also reducing installation and infrastructure costs.
The Easy Way to Bluetooth 4.0 Implementation
Product developers are already getting to grips with the new Bluetooth 4.0 wireless
standard. As markets for these new devices become established, and as further new
application opportunities emerge, they will need to be able to add Bluetooth 4.0 capabilities
to new products without becoming involved in low-level implementation challenges such as
analogue and RF design, integrating the various required protocols, and implementing the
host-controller interface supporting connection to the main application processor. Frequently,
product development teams are focused at the application level and do not have in house
expertise to complete these tasks. To overcome these barriers the organisation may choose
to acquire the needed expertise organically or hire a consultant. In either case, this can add
to development costs and delay market introduction. In the Bluetooth space, there is a
precedent for semiconductor vendors to offer a system-on-chip solution that builds in
solutions to most or all of these challenges.
One such vendor is Toshiba Electronics, which is a founding member of the Bluetooth SIG
and has been involved in Bluetooth standardisation and implementation for more than a
decade. The company has already delivered a number of Bluetooth LSI solutions to the
market, which support the version 2.1 and 3.0+ Enhanced Data Rate (EDR) standards.
These include the TC35655 single-chip CMOS IC with embedded ARM9 application
processor, which supports Bluetooth profiles such as Hands-free and Audio Streaming and
is used in the automotive space. .
To help speed up time to market and cut development costs for emerging generations of
Bluetooth 4.0 products including LE technology, Toshiba has developed the TC35661. This
new device supports Bluetooth 4.0 covering Bluetooth Classic (3.0) and Bluetooth Low
Energy (BLE), enabling use in single-mode or dual-mode applications. It is fabricated using
65nm RFCMOS technology, which delivers die-size advantages, and features internal
voltage management contributing to low overall power consumption and a minimum of
external passive components. A 30µA sniff mode also helps to minimise overall energy
budget ultimately resulting in longer battery life.
The TC35661 RF block offers a robust sensitivity of -91dBm. The device also provides a
high level of integration (figure 2), with features such as an LDO regulator and all of the
necessary RF functionality including a balun, antenna switch and LNA implemented on-chip.
An ARM core with onboard ROM and SRAM handles Bluetooth protocol and data processing
tasks at various speeds. Interface options include UART and USB to connect to a host CPU,
and SPI, I2C, I2S/PCM. Support for IEEE 802.15.2 2/3/4 wire coexistence is also provided.
Finally a set of general purpose IOs are available for controlling various embedded
functions.
Figure 2. Block diagram of TC35661 Bluetooth 4.0-compliant SoC.
Figure 3. TC35661 and standard Bluetooth HCI communication.
The TC35661 is - in combination with standard GATT profiles for BLE and HDP profile for BT
classic - suitable for use in medical, consumer and automotive applications. In order to cope
with quality requirements of the automotive market, the TC35661 can follow the AECQ100
quality standard.
The device can be used with the standard Bluetooth HCI UART host-controller interface.
Alternatively Toshiba can provide a fully integrated Bluetooth stack with a selection of
application profiles, which enables a complete Bluetooth solution without support from an
external host. Figure 3 illustrates standard HCI communications with a host processor.
In order to simplify the design efforts for OEMs and free them from complex interoperability
tasks, Toshiba offers a Bluetooth certified protocol stack, which can be combined with its
various Application Profiles depending on the target application type. Figure 4 shows an
overview of BT 3.0 profiles that can be run with TC35655. An open API is available and a
flexible integration into various OS is achievable. A subset of these profiles can be run within
the TC35661.
Figure 4. Bluetooth Classic software configuration.
A further step to simplifying Bluetooth system design is the complete software integration
model for BLE or Bluetooth classic. Figure 5 shows an example of an embedded system
software architecture for BLE.
It is also possible to achieve a dual mode architecture (classic + BLE) by embedding the
related stack and profiles onto the TC35661. This can serve the legacy Bluetooth as well as
the new BLE standard.
Figure 5. Bluetooth BLE software configuration embedded into TC35661.
The Bluetooth SIG describes Bluetooth Dual mode solutions as “Smart Ready”, and
Bluetooth BLE only solutions are called “Smart”. Suppliers may tag such products
accordingly.
To assist designers further and speed up time to market for new LE and dual-mode
applications, the supporting evaluation board or USB sticks, and PC-based tools enable
developers to exercise the full functionality of the device, configure parameters, and monitor
trace data to verify operation of the HCI or API (figure 6).
Figure 6. Configuring the TC35661 evaluation board.
Conclusion
Since its arrival in the wireless networking marketplace, Bluetooth has been enthusiastically
adopted within a relatively small world of applications. With the arrival of the version 4.0
standard adding LE technology, and new system-on-chip devices supporting this enhanced
functionality, Bluetooth will open up a much wider universe of applications based on smart,
low-power devices.
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For more product information visit http://www.toshiba-components.com/wireless/index.html or our Toshiba
Electronics Europe's web site at www.toshiba-components.com Contact details:
Toshiba Electronics Europe,
Hansaallee 181, D-40549 Düsseldorf, Germany
Tel: +49 (0) 211 5296 0 Fax: +49 (0) 211 5296 792197
Web: http://www.toshiba-components.com
E-mail: Wireless: [email protected]
About Toshiba
Toshiba Electronics Europe (TEE) is the European electronic components business of Toshiba Corporation,
which is ranked among the worldʼs largest semiconductor vendors. TEE offers one of the industry's broadest IC
and discrete product lines including high-end memory, microcontrollers, ASICs, ASSPs and display products for
automotive, multimedia, industrial, telecoms and networking applications. The company also has a wide range of
power semiconductor solutions as well as storage products like HDDs, SSDs, SD Cards and USB sticks.
TEE was formed in 1973 in Neuss, Germany, providing design, manufacturing, marketing and sales and now has
headquarters in Düsseldorf, Germany, with subsidiaries in France, Italy, Spain, Sweden and the United Kingdom.
TEE employs approximately 300 people in Europe. Company president is Mr. Takashi Nagasawa.
Toshiba Corporation is a world-leading diversified manufacturer, solutions provider and marketer of advanced
electronic and electrical products and systems. Toshiba Group brings innovation and imagination to a wide range
of businesses: digital products, including LCD TVs, notebook PCs, retail solutions and MFPs; electronic devices,
including semiconductors, storage products and materials; industrial and social infrastructure systems, including
power generation systems, smart community solutions, medical systems and escalators & elevators; and home
appliances. Toshiba was founded in 1875, and today operates a global network of more than 550 consolidated
companies, with 202,000 employees worldwide and annual sales surpassing US$74 billion.
For more company information visit Toshiba's web site at www.toshiba-components.com
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