Palm OS Support for Bluetooth by Semaj1212

VIEWS: 141 PAGES: 23

									Palm OS Support for Bluetooth
Chicago Palm Programmers Group Meeting February 27, 2001

Karen Jeffrey DePaul University and Forall Systems

Sources for talk
• Palm Source Presentation by Peter Easton 205 Bluetooth and Palm OS®

• Palm’s Bluetooth Wireless Technology Page

• Palm’s Bluetooth Whitepaper _bluetooth_whitepaper.pdf

• Palm Source Bluetooth Lab •

Support for Bluetooth
• • • • What is Bluetooth? Palm’s Bluetooth Hardware Palm OS Support for Bluetooth Palm’s Bluetooth API

What is Bluetooth?
• Open wireless communication standard

• Focused on mobile wireless links
– Small, low cost, low power consumption

• Allows small ad hoc wireless networks
– Piconet
• 1 master and up to 7 active slaves

– Scatternet
• Communication between Piconets

What is Bluetooth?
• 2.4 GHz Open band
– Globally available – Other devices include microwave ovens, cordless phones – Frequency hopping and Time Division Multiplexing

• 10 – 100 meter range
– Up to 8 active devices can be in the same piconet

• 1 Mbps gross rate • Simultaneous voice/data capable
– 432 Kbps (full duplex), 721/56 Kbps asymmetric – Or 3 simultaneous voice full duplex calls – Or a combination of voice and data

Related Standards
• IrDA: Infrared Data Association
– Infrared “beaming” – Short distances (~1 meters) – Point-to-point, line-of-sight communication

• 802.11B and HomeRF
– – – – Higher bandwidth Don’t support voice More expensive Require more power

General Bluetooth Status
(as of Unplugfest in November 2000)
• 1.0B specification had problems • 1.1 specification fixes most of the problems (published October 2000) • Most vendors have point-to-point working • Some vendors have point-to-multipoint working • Scatternet will not happen in this generation of radio

Palm’s Bluetooth Hardware
• Palm’s Bluetooth Initiative started by 3Comm over 2 years ago • Bluetooth will at first be an add-on and when prices drop will be integrated • Power
– 10 meter range between Palms – 30 meter range to LAN access point

• Uses serial port (limited to 115,200 bps)

Bluetooth System Components
• Radio unit
– actual radio transceiver which enables the wireless link between Bluetooth devices

• Baseband unit
– hardware, consisting of flash memory and a CPU, which interfaces with the radio unit and the host device electronics at the hardware level

• Software stack
– driver software or firmware which enables the application level software to interface with the baseband unit

• Application software
– implements the user interface and overall functionality of the Bluetooth device

Hardware Operation
• The Palm Vx powers the Bluetooth module • Bluetooth module monitors Tx and RTS pin
– Goes into standby mode when lines not powered

• Bluetooth module asserts HotSync interrupt to wakeup Palm
– HotSync notification sent to Bluetooth library

Palm’s Product Roadmap
• Hardcase for Palm Vx
– Seed some developers in Jan/Feb 2001
• Software and hardware is alpha

– General developer availability Q2 2001

• Hardcase for other Palms? • Bluetooth on SD card? • Bluetooth integrated into Palms
– Perhaps 2002 or 2003

• Licensees will also provide support

Palm OS Bluetooth Support Goals
• • • • Consistent UI and API Conform to version 1.1 of Bluetooth specification Emulate serial ports via Virtual Serial Port Driver Allow desktop HotSync with selected Bluetooth PC cards • Allow HotSync with IP using cell phones & LAN access points • Maintain compatibility with Wireless Internet Kit

Bluetooth Connections
• Voice or data connections
– Asynchronous Connectionless (ACL)
• Used for data • Supported by Palm OS

– Synchronous Connection-Oriented (SCO)
• Used for voice • Not supported by Palm OS this release

• Paired or temporary Connections
– Temporary connections have to be discovered
• Average time to connect: 2.56 seconds

– Paired connections are more secure and faster
• Average time to connect: .64 seconds

Network Topology
• Piconet
– 1 master and up to 7 active slaves – Supported by Palm OS

• Scatternet
– Communication between Piconets – Not supported by Palm OS

Device Discovery
• General
– Used by devices that need to discover devices that are made discoverable continuously or for no specific condition with General Inquiry Access Code. – Supported by Palm OS

• Limited
– Allows discovery of devices that are set to scan for inquiry messages with the Limited Inquiry Access Code. – Not supported by Palm OS

Bluetooth Security
(Palm OS will support modes 1&2)
1. non-secure
– device does not initiate any kind of security procedure

2. service-level security
– more flexibility in application access policies is allowed

3. link level security
– device sets up security procedures before the link setup is completed. – Link level security provides applications with knowledge of "who" is at the other end of the link and provide authentication, authorization, and encryption services

Bluetooth API
• General Management
– ME: Management Entity Functions – For discovery, ACL links and global Bluetooth settings

• SDP: Service Discovery Protocol
– For advertising and discovering services to/from remote devices

• Sockets
– RFCOMM: Cable Replacement Protocol
• Serial line emulation protocol

– L2CAP: Logical Link Control and Adaption Protocol
• Allows higher level protocols and applications to transmit and receive data packets.

Typical Bluetooth Operation
• Discover single or multiple devices • Create an ACL (data) link to the device • Create a socket
– SDP: Service Discovery Protocol – RFCOMM: Used by Virtual Serial Driver – L2CAP: Data Connection

• Pass Data • Close Socket, close ACL link

Palm OS Bluetooth Virtual Serial Port
• • • • • • Opens background thread for the Bluetooth stack Supports only one active serial channel at a time Uses a blocking open call Opened explicitly as client or server Used as a client by: PPP, HotSync, Telephony As a server, advertises list of services available

Expected Release Dates for Palm OS Bluetooth Support
• Not in OS 4.0
– However OS 4.0 will be “Bluetooth-aware”

• Bluetooth libraries will be release before “OS 5.0”
– Will be “OS 4.0 with Bluetooth” – Runs on POSE – Around 200K

To top