My question is very basic.I need to know where does all Bluetooth profile such HID, HFP or HSP loaded in Bluetooth stack? Is it in Host layer or in Bluetooth Hardware Chipset such as USB dongle/module or in both Host and Chipset Side?
According to my understanding, we can implement Bluetooth profiles on Host side using packages like BlueZ but at same time Bluetooth chipset which is connected to Host should need some sort of firmware and logic(like CSVD, A-law ) inside its chipset.
A quote found in BlueZ Android package doc: "Wideband Speech support in HFP it is required that BT chip assumes mSBC codec". This means Host layer can implement that Profile only if BT chipset provides the low-level support like mSBC.
My Answer is like this: " We can build any Bluetooth Profile say 'X' on Host layer if BT chipset is equipped with underlining Low-level firmware which support the Profile 'X'".Please agree or disagree with my understanding.
PFA diagram of my understanding
Position of profile and its low-level firmware
I need to select a USB Bluetooth dongle compatible to Raspberry Pi and customize the HID and HFP using BlueZ.
Advance Thanks to all Bright minds!
There are multiple ways how Bluetooth functionality is implemented in a system based on how much is implemented in the controller and host.
Everything in the controller - App, Upper stack, may or may not HCI(lower and upper stacks communicate through HCI commands and events), Lower stack. Example: Most of Bluetooth Mouse, Keyboard etc, where a single controller is responsible for everything (Bluetooth, RTOS/scheduler, Controlling LED's in the device, etc)
App in Host and lower and upper part of stack in controller. May or may not implement HCI in controller.
Example: Where we use a dedicated Bluetooth chip and integrate it with the Device. Here device will transmit application data to the Dedicated Bluetooth chip. All the Bluetooth protocol related things will be done from BT controller/chip. If you are using an HC-05 module with Arduino module, Arduino will transfer the serial data to the HC-05 module.
App and upper stack in host and lower stack in the controller. Bluez, Bluedroid and all other stacks in Operating systems are of this type. This will communicate with the controller with HCI commands and events.
Example: Mobile phones, Computers, TV with Bluetooth etc (Devices having a powerful Application processor)
So lets assume you are asking about the 3rd type. In this case your assumption is correct. Here all profiles are implemented in the host only. But protocols/codec needed to support them will be implemented in the controller(either firmware or hardware block). For example GAP(For BR-EDR) is implemented in the host but encryption and decryption algorithms are implemented in the controller as Firmware or hardware blocks. For A2DP profiles audio codec/decoders will be implemented in the controller. BT chip then transfers this audio data to host with I2S or other protocols. For BLE Security manager profile, encryption/decryption algorithm is implemented in the host itself, But whitelist, auto connection etc, will be implemented in the controller.
My Answer is like this: " We can build any Bluetooth Profile say 'X' on Host layer if BT chipset is equipped with underlining Low-level firmware which supports the Profile 'X'".Please agree or disagree with my understanding.
For BlueZ use case this is correct. You need to use the controller with the required hardware capabilities(Firmware + hardware resources).
For the scenarios 1 and 2 the profiles and supporting protocols will be implemented in the controller.
Related
I'm developing an Android app that manages multiple Bluetooth LE devices such as speakers, lighting devices, various sensors.
For user convenience, these devices have to be 'grouped' together and only accessible through a single Bluetooth connection.
Is programming some kind of custom intermediary hardware to serve as an interface required in this case or are there some better solutions?
It is possible to group bluetooth device by the profiles they implement https://en.wikipedia.org/wiki/List_of_Bluetooth_profiles . In Android the profile of a bluetooth device can possibly be determined like in In Android, how to get the profile of a connected bluetooth device?
I’m working on a project that uses BLE (Bluetooth Low Energy) protocols for transferring data and am currently limited to my MacBook due to some Admin permission constraints on my work machine (running Windows).
I need to find a USB adapter that supports Bluetooth 4.0 Tx/Rx, however I am ONLY finding these dongles that solely support Windows distros. So my question:
1) Why is this? Is Bluetooth SIG or at least BLE somehow a propriety protocol patented or somehow bound to Microsoft? I mean, there exist iOS libraries for high-level BLE management, so...
2) Am I just missing the product I’m looking for and there are such accessories compatible with a Unix based OS?
Who said USB dongles only support Windows? On the contrary, I haven't heard about a single USB dongle that doesn't support Linux. Bluetooth SIG has defined and specified HCI over USB and every device uses that protocol (however some device specific code is often needed to initialize the device). See a list of some tested devices at https://github.com/50ButtonsEach/fliclib-linux-hci/blob/master/README.md#bluetooth-controllers. Those should work with Mac OS X as well, but if the computer already has a built in Bluetooth chip you might need to adjust the currently used device.
I have been asked to figure out how to achieve bluetooth communication through an off-the-shelf dongle (in this case a dongle utilizing the Broadcom BCM2045 chip) using the FTDI Vinculum 2 (VNC2) USB controller. I have custom firmware written for the VNC2 to communicate with a generic USB device with the VNC2 acting as the host, and I can successfully read the VID and PID from the dongle as well as the USB device class, subclass, and protocol. I can also send data to the dongle using the bulk data endpoint and I believe the device is receiving though I have no way to tell at the moment.
So I believe I can communicate with the dongle, the problem is I have no idea WHAT to communicate to it in order to set it up in discoverable mode or to pair it with another discoverable device, nor how to actually transmit data through the wireless link once it is paired. I don't even know if there exists a standard communication protocol for this type of thing or if every device will be different. I have a vague understanding of the bluetooth protocol stack and it is my understanding that I won't be required to fully understand that as it should be implemented in the dongle on one end and in the android smartphone that we hope to connect to on the other end. Like I said, I can currently send data to the bulk endpoint, is it true that this endpoint is only for data transfer over the wireless link and I will need to connect to a different endpoint in order to send setup/configuration messages to the dongle?
In short, I need to know what data to send over the USB bus to control any generic bluetooth dongle if possible or at least one specific bluetooth dongle. I have a USB port sniffer but the complexity of the output while using the dongle to communicate is staggering and I doubt I'll ever figure it out.
Thank you in advance.
Bluetooth dongles communicate with host software stack using HCI (host control interface), which is defined in the Bluetooth spec. For reference, you can look at source code for the open source BlueZ stack (standard linux stack). You could run BlueZ on linux talking to your USB dongle, and use hcidump to capture actual packets going across HCI. You can also check out hcitool and hciconfig for performing specific actions.
Can a WindowsCE device connect so more than one BlueTooth device? The device needs to both serve as a BlueTooth hands-free speaker for a phone and connect to a third device via a serial BlueTooth connection.
Can an application do this without the need of a speciel driver?
You must understand that Windows CE is a modular OS and any specific platform capabilities are implemented by an OEM. An OEM can create a Windows CE device with absolutely no Bluetooth support or they might choose to implement just a Bluetooth client profile (say as a bluetooth audio device) or they may choose to implement a Bluetooth server so they can consume a Bluetooth serial device. They may also choose to implement both. Beyond what the OEM does in software, the hardware itself might allow only one or the other (or both or neither for that matter).
The short of this is that we can't actually answer your question becasue there is no generic answer that fits all devices. You have to ask the Device OEM what they support and if they can extend that support if they don't support what you need.
I'm looking to implement the Bluetooth protocol over a physical Wi-Fi based transport, if that makes sense.
Basically my phone has Bluetooth, and my laptop has a Wi-Fi card (802.11a/b/g).
I know that Wi-Fi operates over the range 2.412 GHz - 2.472 GHz, and that Bluetooth operates over the range 2.402 GHz - 2.480 GHz.
I couldn't help but notice the overlap here. So my questions are:
What sort of low-level APIs would I need (preferably in C, on Windows) in order to send a signal out at certain frequencies on the Wi-Fi card?
Would I be able to implement a Bluetooth stack on top of this?
So basically, can I transmit Bluetooth using my Wi-Fi card as essentially a radio transmitter?
Thanks
Implementing the Bluetooth protocol over a physical Wi-Fi based transport does make sense!
Bluetooth high speed (v3.0) defines the possibility to use alternate MAC/PHY layers, known as AMP feature. The L2CAP and higher layer protocols from Bluetooth can be transmitted over a Wi-Fi MAC/PHY layer rather than a Bluetooth MAC/PHY layer with a resulting higher throughput. Some products are on the marked supporting this - look for 'Bluetooth High Speed', AMP or Bluetooth v3.0 support.
No, you can't do this. Bluetooth devices are typically wrapped up all in one chip. Plus, they use completely different modulation techniques. No low-level anything is going to allow you to transmit anything different, unless you are flashing the device. Even then, it may not get you much closer.
Bluetooth Modulation Information:
http://www.palowireless.com/infotooth/tutorial/radio.asp and http://classes.engr.oregonstate.edu/eecs/spring2003/ece44x/groups/g9/jon_gillen/white_paper_jon.pdf
About the only thing you can share between WiFi and Bluetooth devices is the antenna. (Assuming only one device is using it at a time... don't blast 32mW into the receiver of the other radio!) The radio itself is all wrapped up into the same chip. The same is generally true for WiFi.
Bluetooth and Wifi have different phy layer protocols and thats what is coded into their chips, hence you can't use one chip to transmit packets of the other protocol.
Moreover most of the chip vendors, do not expose any RF logic.
Technically yes but there are some things to consider such as the pre existing coding on the chip and if the chip can support Bluetooth coding as well as wifi coding, I mean if you have two separate wifi chips go ahead and try but be warned I tried and nearly killed my computer because of preexisting copyright protection coding on other parts of my pc that prevented any programs on the chip from starting until I reset the chip to factory defalts.