Providing Bluetooth Functionality on Embedded Devices: A look at Embedded Operating Systems and Bluetooth Stacks

Brian FoxSupervisors:Dr Greg FosterProf. Peter Clayton

Introduction

Part of the Automated Wireless Identification System project

Specifically focused on how to expose Bluetooth functionality in embedded devicesI.e. design and build a custom OS image

which exposes some form of API allowing access to the Bluetooth stack

Timeline

Look at the various OS builders in use for various embedded OS’sThis entailed identifying and studying the

architecture of some embedded OS’s on the market and looking at the tools provided to help create a custom image for that OS

Create and build own custom Windows CE .NET platform

Problems involved with Embedded Systems Design

Hardware / Software partitioning What parts of the solution should be

implemented where? Can lead to integration problems in later

development stages

Power Some microprocessors can operate in “sleep

mode” and only wake up on a timer tick

Debugging Hooks provided in microprocessor circuitry

Embedded Operating Systems

Highly modular/componentisedSupport wide variety of target

hardware and processors through use of BSPs

Real-timePower management

Windows CE .NET

Designed around mobile devices Minimum footprint of 200k

Actual footprint currently

Power management “Instant On” Control of device level power states

Wide range of board support packages (BSPs)

Microsoft is the only vendor to supply a Bluetooth stack with the operating system

Windows CE .NET Architecture

OEM Hardware

Embedded Shell

ApplicationsApplications

WIN32 APIsCOREDLL, WINSOCK, OLE, COMMCTRL, COMMDLG, WININET, TAPI

Windows CE Shell Services

Remote Connectivity

WIN32 APIsCOREDLL, WINSOCK, OLE, COMMCTRL, COMMDLG, WININET, TAPI

Windows CE Shell Services

Remote Connectivity

KernelLibrary Blue-

tooth

GWES Device Manager

FileManager

TCP/IP

KernelLibrary Blue-

tooth

GWES Device Manager

FileManager

TCP/IP

OALBootloader

DriversDevice Drivers

File DriversOAL

BootloaderDrivers

Device Drivers

File Drivers

Platform Builder

Integrated Development Environment Provides the means to create, build, deploy and

debug a custom image of the OS Provides an emulator to allow for simultaneous

hardware and software development Automatically determines dependencies between

modules Practical experience

Have built a headless operating environment exposing Bluetooth functionality through the WINSOCK API

Platform Builder

QNX Neutrino

Designed around microkernel and central software bus

“Plug-in” type architecture Inter-process communication via message

passing handled by the microkernel OS exposes standard POSIX API Platform creation either manual or through

use of the Momentics Professional Edition IDE Will run on multiple host platforms

QNX Neutrino Architecture

Wind River VxWorks

Modules implemented on top of the core OSCore OS consists of a microkernel and

debug agent and interacts with the BSPPlatform creation either manual or

through use of the Torando IDE

Bluetooth Stacks

Means by which the OS and applications access and control the Bluetooth hardwareExpose an API to application developers

Modular in concept and designMay need to be ported to a specific OSBluetooth Qualification

Need to implement all core stack layers and Generic Access Profile and Serial Port Profile

Microsoft Bluetooth Stack

Stonestreet One Bluetopia

Where to from here?

Test and debug practical imageHopefully deploy onto a development

board for full testing with the other team members

Questions?