Bluetooth Primer - Motorola DragonBall MC9328MX1 Reference Manual

Chapter 16
Bluetooth Accelerator (BTA)
This chapter describes the Bluetooth Accelerator (BTA) which, controlled by software running on the
ARM core, implements baseband protocols and other low-level link routines of the Bluetooth baseband.
This chapter covers the following main topics:
•

Bluetooth Primer

• BTA Overview
• Pin Configuration for BTA
• Programming Model
16.1 Bluetooth Primer
Bluetooth is a short-range radio link intended to replace the cable connecting portable and/or fixed
electronic devices. Key features of Bluetooth technology are robustness, low complexity, low-power, and
low cost.
Bluetooth operates in the unlicensed ISM band at 2.4 GHz and uses frequency hopping to combat
interference and fading. A symbol rate of 1 Mbps utilizing binary shaped FM modulation minimizes
transceiver complexity. A slotted channel is applied with a nominal slot length of 625 µs. For full duplex
transmission, a time division duplex scheme exchanges packets through the channel. Each packet is
transmitted on a different hop frequency and typically occupies a single slot, however can extend to a
maximum of five slots.
A Bluetooth system provides a point-to-point connection (only two Bluetooth units involved), or a
point-to-multipoint connection where the channel is shared among several Bluetooth units. Two or more
units sharing the same channel (set of hopping frequencies) form a piconet. One Bluetooth unit acts as the
master of the piconet and any the other units act as slaves. A maximum of seven slaves can be active in the
piconet, and many more slaves can remain locked to the master in a so-called parked state. Parked slaves
cannot be active on the channel, however remain synchronized to the master.
Multiple piconets with overlapping coverage areas form a scatternet. Each piconet has a single master, and
a master in one piconet can serve as a slave in another piconet. Slaves can participate in different piconets
on a time-division multiplex basis. The piconets are not synchronized in time or frequency.
A Bluetooth system consists of a radio unit, a link control unit, and a support unit for link management and
host terminal interface functions (see Figure 16-1 on page 16-2). The radio, link controller, and link
manager are described in the Specification of the Bluetooth System, version 1.1.
MOTOROLA Bluetooth Accelerator (BTA) 16-1