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Integrating Bluetooth on low-power buses

HW-255T. Integrating Bluetooth on low-power buses. Abhinav Gupta Program Manager Microsoft Corporation. Agenda. Transport connectivity – challenges & goals Delivering great Bluetooth experiences Sample Bluetooth integration You’ll leave with examples of how to

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Integrating Bluetooth on low-power buses

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  1. HW-255T Integrating Bluetooth on low-power buses Abhinav Gupta Program Manager Microsoft Corporation

  2. Agenda • Transport connectivity – challenges & goals • Delivering great Bluetooth experiences • Sample Bluetooth integration You’ll leave with examples of how to • Develop for Bluetooth connectivity using low-power transports • Incorporate vendor-specific customizations

  3. Improved power efficiency calls for lower power Bluetooth transport connectivity.

  4. Transport connectivity – challenges & goals • USB controllers are scarce & targeted for higher-bandwidth apps • Goal: provide a transport extensibility model so you have connectivity options • Bluetooth controllers using lower power buses rely on vendor-specific customizations • Goal: enable implementation flexibility so integration is easy for you

  5. Transport connectivity – challenges & goals • Performance impact when using lower power transports • Goal: ensure higher-layer Bluetooth scenarios remain transport agnostic so you can deliver the same experiences • Voice-based scenarios have stricter latency requirements • Goal: support an alternate voice channel (offloading) so you can achieve optimal audio quality while further reducing power

  6. demo Bluetooth on QC and TI ARM platforms Tablet with several Bluetooth peripherals Speakers – listening to music HID – using a keyboard & mouse Bluetooth transport: high-speed UART

  7. Sample Bluetooth integration

  8. Windows 7 stack architecture • A look at Windows 7 • USB Bluetooth controller support • BthPort.sys: core driver • BthUSB.sys: USB miniport driver • Enumeration via PnP • Inbox profiles • HID, OPP, PAN, HCRP, SPP, DUN BthPort.sys SDP L2CAP SCO HCI BthUSB.sys USB port driver Bluetooth controller MSFT component 3rd party H/W

  9. Windows 8 stack architecture • A look at Windows 8 • Transport connectivity options • BthMini.sys: extensible driver • Transport driver: vendor-supplied • Controller drivers: meant for data I/O, power up & idle/wake • Enumeration via ACPI • ACPI table definition • Enables for the same driver to be used across platforms BthPort.sys BthMini.sys BthUSB.sys Bluetooth transport driver Framework extensions USB port driver Controller driver(s) Bluetooth controller MSFT component Vendor component 3rd party H/W

  10. Sample system connectivity • System designer – required controllers: • Data I/O • Power on/off • Idle/wake signaling (Bluetooth enable, host wake) • Chosen controllers: • HS-UART • I2C • GPIO System core I2C GPIO GPIO HS-UART BT_ENABLE DATA_IO HOST_WAKE Bluetooth controller POWER Power Management IC

  11. Sample ACPI description for Bluetooth • Device (BTH0) • { • Name (_HID, "ABCD_BTH") //where "ABCD" is vendor name; • Method (_CRS, 0x0, NotSerialized) • { • Name (RBUF, ResourceTemplate() • { • //UART Serial Bus Descriptor • UARTSerialBus (0xC0, LittleEndian, DataBitsEight, StopBitsOne, FlowControlHW, • 115200, 480, 32, ParityTypeNone,"\\_SB.UAR1", , ) • //I2C Descriptor • ... • //GPIO Descriptor • ... • }) • Return (RBUF) • } • }

  12. Sample stack architecture • Dependent controller drivers • UART, I2C, GPIO • Based on frame extensions (Cx) • WDK samples – easier development • Bluetooth transport driver • KMDF WDK sample – UART • Vendor supplied for: • Device configuration (& F/W update) • Power up & idle/wake • Combo-chip support • Radio on/off BthPort.sys BthMini.sys Bluetooth UART transport driver Bluetooth transport driver I2C Cx Framework extensions UART Cx GPIO Cx I2C driver Controller driver(s) UARTdriver GPIO driver Bluetooth controller MSFT component Vendor component 3rd party H/W

  13. Sample device configuration • Setting up the Bluetooth controller • Configuration done through vendor-specific commands • Enabling implementation flexibility • Integrated within transport driver • Separate initialization library BthPort.sys BthMini.sys Initialization Lib Bluetooth UART transport driver I2C Cx UART Cx GPIO Cx I2C driver UARTdriver GPIO driver Bluetooth controller MSFT component Vendor component 3rd party H/W

  14. D0: Active Core stack device power states & transitions • D2: Low Duty Cycle • How does the Bluetooth stack achieve energy efficiency? • You can leverage this behavior and easily integrate it into your designs S0 • D3: Off WAKE ON IDLE Sx OFF

  15. Sample Bluetooth power-up & idle/wake • Power up • I2C – Bluetooth power on • GPIO – Bluetooth enable • Idle • GPIO – armed for wake • GPIO – Bluetooth disable • Wake • GPIO – Host wake detected • GPIO – Bluetooth enable System core I2C GPIO GPIO GPIO GPIO HS-UART BT_ENABLE DATA_IO HOST_WAKE Bluetooth controller POWER Power Management IC

  16. Sample combo-chip & radio on/off support • More radios becoming integrated • Sample combo-chip device • Transport driver now a bus driver • Can accommodate for changing H/W configurations • Radio on/off • A unified radio management experience across system components • Vendor-provided DLL is easy to integrate BthPort.sys FM GPS Radio manager BthMini.sys Bth on/off DLL UART bus driver Bluetooth transport driver I2C Cx UART Cx GPIO Cx I2C driver UARTdriver GPIO driver Multi-function device (BT/FM/GPS) MSFT component Vendor component 3rd party H/W User-mode component

  17. Bluetooth profile support

  18. Supported profiles • Inbox profiles • HID, PAN, OPP (file transfer), HCRP (print) • HFP (with sideband support), A2DP, AVRCP • Partners can develop profiles on top of the stack

  19. Sample sideband SCO audio (voice) support • Voice has strict latency requirements • Isochronous channel in USB ensures on-time delivery • Low-power buses don’t have a prioritization concept • Rely on an I2S/PCM channel for improved audio quality • Enabling flexibility in the HFP driver • USB: operates in “in-band” mode • Low-power buses: operates in “side-band” mode 3rd party app (e.g. Skype) Audio core CallButtons API HFP driver Audio driver Bluetooth stack Transport driver Bluetooth controller I2S HS-UART MSFT component Vendor component 3rd party H/W

  20. Performance & CPU utilization (back to the demo)

  21. Performance & CPU utilization analysis • File transfer (object push profile) – receive & transmit scenarios • Internal HS-UART (no DMA) vs. external USB radio on the same platform • For about the same throughput, CPU utilization is higher for USB Throughput CPU Utilization USB:~68% more USB:~17% faster USB:~2% faster USB:~6% more

  22. Windows certification for Bluetooth • Our stack provides a platform so you can easily integrate and innovate • Benefit from tight integration with the power management framework • Leverage inbox experiences and develop more higher-layer profiles • We need your help in designing Bluetooth controllers that deliver the highest quality experiences to our customers

  23. Final remarks • Developed for Bluetooth connectivity using low-power transports • Bluetooth stack is enabling implementation ease & flexibility around: • Transport connectivity, device configuration, power-up & idle/wake signaling, combo-chip support, and unified radio management • Bluetooth stack is delivering key end-user experiences

  24. Call to action • Meet certification requirements for your system • Follow extensible transport Bluetooth bring-up guidelines: • ACPI table description – device properties & interconnectivity • Bluetooth transport/bus driver • Dependent controller drivers • Audio driver

  25. Related sessions • [Session 774] Building great Windows 8 systems • [Session 251] Introducing low-power buses for Windows 8 • [Session 254] Connecting Bluetooth Low Energy devices to Windows

  26. Further reading and documentation • Bluetooth Extensible Transport Enumerations • Bluetooth Extensible Transport Structures • Bluetooth Extensible Transport IOCTLs • Bluetooth Software Radio Switch Function Prototypes • Bluetooth Devices Reference • Windows Hardware Dev Center • Windows DevCenter • More about Bluetooth • http://www.bluetooth.org

  27. thank you Feedback and Questions: http://forums.dev.windows.com Session Feedback: http://bldw.in/SessionFeedback

  28. © 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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