1. technology and computing

 How to Simplify Implementations for “Bluetooth® Smart” Low Energy
Applications
By Toshiba Electronics Europe
Summary
The new Bluetooth Low-Energy (LE) technology has been specified by the Bluetooth® SIG
(Special Interest Group) within the latest Bluetooth® 4.0 standard to provide an effective
platform for a new generation of smart, networked applications. The path to easy access to
this technology is possible via enhanced full system LSI devices and embedded software
integration. 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: Bluetooth® is an established standard
Since the Bluetooth standard was first published, Bluetooth Special Interest Group (SIG)
members and developer communities have been quietly filling professionals´ and
consumersʼ lives with short-range wirelessly-connectable products such as mobile phones,
headsets, PC dongles or simple wireless cable replacement devices. According to IMS
Research, more than 2.6 billion Bluetooth-enabled devices will ship in 2015 in the PC,
automotive, consumer and health or sport market.
Bluetooth has established itself as a worldwide-accepted standard amongst professionals
and consumers. Due to its versatile usability for short range wireless communication by
offering various standard profiles for audio and data Bluetooth has found its way into
manifold applications and systems. It features data rates up to 3 Mbps (with Bluetooth EDR:
enhanced data rate) and up to 24Mpbs(with Bluetooth HS: high speed) through its
combination with a WIFI physical carrier. Bluetooth offers advantages such as low design
risk for product developers, fast time to market, access to a large pool of developer skills,
and certified interoperability with certified compliant devices from other manufacturers.
Silicon and software is available at competitive terms from various vendors. Interoperability
of system solutions enhances the marketability of Bluetooth devices, encourages
1 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. (see Figure 1, Bluetooth
History)
Figure 1: Bluetooth History
Bluetooth has become a key factor driving almost universal consumer awareness of, and
demand for, wireless connectivity between personal and mobile devices. 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 networking, smart
metering, personal wellness monitoring and home and industrial automation present a
diverse and growing range of further opportunities for Bluetooth as a ubiquitous, low-cost, ad
hoc wireless networking technology.
Bluetooth on the move
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 (also called Bluetooth Classic) and 3.0 standards are not
2 well suited to ultra low-power applications such as those used in tiny sensors that may need
to operate from a small power source, such as a button cell, for periods as long as several
years without requiring replacement of the cell.
The Bluetooth SIG has been proactively preparing the market by defining a new 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 or BLE) enhances
the usability 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 2 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 2. Speeding up connection/disconnection processes.
3 Bluetooth LE Applications
With this LE technology, the Bluetooth SIG is seeing the first new product introductions to be
focused on healthcare and fitness applications. 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 including
PCs, tablets and mobile phones to permit easy wireless syncing, enabling data to be
collected, processed, analysed and shared easily and simply. In order to ensure
interoperability amongst those low energy devices, the Bluetooth SIG has created common
markings for tested devices: “Smart” and “Smart Ready”. Smart is applied to Bluetooth Low
Energy only devices; Smart Ready is a name for devices that comply with the whole BT 4.0
standard, including Bluetooth Legacy specifications (Bluetooth EDR). In this way the legacy
and the new Bluetooth world can be connected successfully.
Today you already find hundreds of Smart and Smart Ready devices on the market.
“Classic” device manufacturers are eager to migrate their existing products to the new
standard. IMS Research (2012) forecast that by 2017 the shipment of Bluetooth classic
devices will nearly end and will be completely replaced by Smart Ready devices.
Overcoming Implementation Challenges
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. Project managers need to find an effective way to build in
latest Bluetooth technology.
4 There are two main usual options:
1. Choose a readymade module incorporating the latest silicon solutions and firmware, or
2. Design-in a new circuit and add a software solution by themselves.
Option 1 offers a quick time-to-market but means a higher bill of material (BoM); Option 2
enables an optimized in-circuit solution, however it requires specific Bluetooth know how.
The development organisation may choose to acquire the needed expertise organically or
hire a consultant, which adds cost again.
In either case, this can add to development costs or 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 millions of Bluetooth LSI devices, largely for
automotive market including required protocol stacks and application profiles e.g for audio
streaming, hands free operation or SIM access.
To help speed up time to market and cut development costs for emerging generations of
Bluetooth 4.0 products featuring LE technology, Toshiba has developed the TC35661. This
device supports Bluetooth 4.0 as well as Bluetooth 3.0 EDR, enabling use Smart or Smart
Ready equipment. 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 3), with features such as an LDO regulator for single voltage
supply and all of the necessary RF functionality including a balun, antenna switch and LNA
implemented on-chip. An ARM core with on board ROM and SRAM handles all Bluetooth
protocol and data processing tasks at various speeds. Interface options include UART, SPI,
5 USB 2.0, I2C, I2S/PCM. Support for IEEE 802.15.2 2/3/4 wire coexistence is also provided,
which is a part of the Bluetooth HS standard.
Figure 3. Block diagram of TC35661 Bluetooth 4.0-compliant SoC.
The TC35661 is suitable for use in medical, consumer, industrial and automotive
applications. In order to cope with quality requirements of the automotive market, the
TC35661 follows the AECQ100 quality standard. The device is package in a 5mm*5mm
BGA package with 0.5mm ball pitch, or 7mm*7mm BGA package with 0.8mm ball pitch (to
allow 2 layer PCB).
System Configurations Scenarios
The device can be used with the standard Bluetooth HCI host-controller interface over either
UART or USB (Figure 4). Customers can use 3rd party protocol stacks and profiles on the
host processors and link to the standard HCI software interface. Alternatively, Toshiba can
provide a fully certified Bluetooth stack with a selection of application profiles, which enables
a complete Bluetooth solution without support from an external host.
6 Figure 4. TC35661 in a standard HCI system (example)
To simplify the design process further, customers can also make use of a fully embedded
protocol stack and a selection of embedded profiles (Figure 5). Embedded profiles may
currently be SPP (serial port profile for cable replacement), HID (human interface device for
e.g. remote control) or GATT (generic attribute profile for BLE). A combination of SPP and
GATT is also feasible (dual mode). This firmware is embedded in the Bluetooth LSI ROM,
and has all necessary Bluetooth Qualification approvals (called QDID). Designers can re-use
these QDID to ease the Bluetooth SIG device listing significantly. This relieves the designer
of Bluetooth qualifications and unloads the host MCU of any specific Bluetooth task. The
software interface between host and Bluetooth device is a high level API (application
program interface).
7 Figure 5: TC35661 with embedded stack and profiles (example)
Another step towards easier integration can be achieved by the development of standalone
Bluetooth subsystems (Figure 6). This involves the replacement of an external host
application MCU by the embedded ARM7 computing power. This is possible for small
application tasks with up to 20kB code size. The actual program code is stored in an external
EEPROM and bootloaded into the LSI RAM upon RESET.
Figure 6: TC35661 standalone system (example)
8 Module Solution
Module manufacturers offer further integration, combining software, system LSI device and a
ready-to-use RF module design with all associated FEC/IC/CE approvals. Modules, such the
PAN1026 from Panasonic Industrial Europe, are a final step to facilitating the system
integration of Bluetooth with minimum specialized efforts.
Development Environment
To assist designers further and speed up time to market for new LE and dual-mode
applications, the supporting evaluation sticks (e.g. from Panasonic) 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 and API interface (figure 7).
Figure 7. 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 featuring 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. Embedded protocol stacks and profiles as well as ready-made
modules pave an easy path to access this technology.
9 ##
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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