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BLUETOOTH KNOW-HOW

emxys Bluetooth know-how

Embedding Bluetooth

Bluetooth products

MIXED DESIGN

DATA ACQUISITION

EMBEDDED INSTRUMENTS

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Bluetooth technology

Bluetooth is a wireless communication protocol conceived to enable high speed data transfer through portable devices. Its physical layer can be implemented as a light weight, small, inexpensive and low power electronic device and therefore is being mainly used for handheld computers and phones within the consumer electronics market. However, its applications within embedded systems are countless and twofold: on one side, Bluetooth enabled embedded systems may communicate with handheld devices extending its capabilities to supervision, control and data acquisition; on other side, embedded systems may communicate between them easily, at high data rates and at low cost up to 100 meters in distance and even more.

Bluetooth is an open specification to provide short-range wireless communications. It operates in the unlicensed ISM band at 2.45 GHz using Frequency Hop Spread Spectrum modulation to avoid interference. There are two kind of devices: Class 2 devices reach up to 10 m with a power of 0 dBm; Class 1 devices reach up to 100 m with 20 dBm1.

Bluetooth communicates a master and a slave device. Usually each device is able to operate as either master or slave at a time. Bluetooth devices have a unique 48-bit address (BD_ADDR) used as identification. This address defines also the way devices negotiate and start radio communication.

The Bluetooth specification defines the implementation of profiles that run over lower layers of the Bluetooth stack. Bluetooth Profiles define a simple way to communicate different devices using a high level protocol. Among several Bluetooth profiles the Serial Port Profile (SPP) was created to make a simple wireless substitution of the RS232 cable that connects many computers and embedded products. The final goal of Bluetooth SPP was to create a low cost alternative to the wire connection.

emx y s has developed a firmware to integrate embedded applications using the Serial Port Profile on top of a qualified Bluetooth 1.1 stack. The firmware features:

• It permits the user to define the class of Bluetooth device and name of the module as seen by other Bluetooth devices.
• It offers Bluetooth security and permits the users define the PIN number to connect with it and with other Bluetooth devices.
• It may behave as Bluetooth slave (accept connections) or Bluetooth master (initiate a connection).
• It may perform inquiries and discoveries of Bluetooth devices around.
• It permits to define the characteristics of the UART (RS232) communications, i.e., baud rate, parity and stop bit.

emxys has the capabilities to embed these products in specific solutions attending any particular needs. Moreover, emxys may develop solutions based in other Bluetooth qualified profiles.

For especific products and applications of this technologies follow this link.