Bluetooth advertising how does it work

This includes: Roles of BLE devices Advertisements Broadcasting, Discovery, Advertisement parameters, Advertisement data Connection establishment initiating connections, accepting connections, Connection parameters Security There are four main GAP roles that a BLE device operates in: Central : a device that discovers BLE peripherals and broadcasters with the capability of connecting to peripherals.

Peripheral: a device that advertises its existence with the capability of accepting connections from a central. Broadcaster : a device that sends out advertising packets without allowing any connections.

Observer : a device that discovers peripherals and broadcasters, but without the capability of accepting connections from a central. Advertisement Channels In the Advertising state, a device sends out packets containing useful data for others to receive and process.

Advertising Channels in BLE Three of these channels are called the Primary Advertising Channels labeled 37, 38, and 39 , while the remaining 37 channels are called the Secondary Advertisement Channels they are also the ones used for data transfer during a connection. Undirected : Directed advertising types accept connection requests from a known peer device, whereas Undirected accept connection requests from any peer device.

Connectable vs. Non-Connectable : determines whether an advertising device allows a connection to be established or not. Scannable vs Non-Scannable : determines whether an advertising device is capable of handling a Scan Request message from an observer or central. Scan Requests and Responses are used to allow devices to advertise more data than can fit into one advertising packet.

Offloading is accomplished by first advertising on the primary channel that points to an auxiliary packet on the secondary channel. Note: Since non -Bluetooth 5 devices will not be able to discover extended advertisements, it is recommended that advertisers also use an advertising set with legacy advertising PDUs for older scanning devices to be able to discover the end device.

Advertising sets are used to send out different types of advertising events simultaneously. Each advertisement set will have different advertisement parameters such as advertising PDU type, advertising interval, and PHY. These are used for broadcasting packets to devices at a set period between two unconnected devices, meaning that more than one device can listen and tune in on these periodic advertisements.

They consist of advertisements sent at a fixed interval with the advertisement data changing from time to time. Audio Accessories. USB Headset. Custom Accessories. Sensors HAL. Context Hub Runtime Environment. Test Development Workflow. Instrumentation Tests. Native Tests. Android Test Station. Test Framework. VTS Dashboard. Lab Infrastructure. Getting Started. Testing with TF. Through Tradefed. Through Suite. Developing TF. XML Configuration. Global Configuration. Advanced Concepts.

Device Manager. Only 8 first characters of the name can be fitted in the advertising data to meet the byte size limit. Option 1 is the simplest one. The stack will automatically fill the advertising data content based on what services have been defined in the GATT database of the application. It is possible to select which services are included in the advertising packets. All services are not automatically advertised, this is configurable using the advertise parameter.

Option 2 is more flexible because it allows the application to have full control over data that is included in the advertising payload. This is especially useful if the application needs to advertise some manufacturer specific data. Note that even when using custom data the AD elements must be formatted according to the Bluetooth specification. Using custom advertising data is beyond the scope of this article, it will be discussed in a separate article later. This article is intended to be used as a quick introduction to BLE advertising, without digging too deep into the details.

Below are some pointers for more detailed information on the topic:. The documents are accessible form the Simplicity Studio main page launcher view. Alternatively, you can check the doc folder within the SDK installation tree, for example:. I can get Mac address for the devices but for name I got such a below numbers in hex for Bitalino and it not seem include device's name.

Knowledge Article. Details Details. Advertising Data Format When a BLE device is advertising it will periodically transmit packets contains information such as: Preamble, Access Address, CRC, Bluetooth address of the sender, etc… The interesting part from application developer perspective is often the advertising payload that is bytes long.

Example 1: The first example shows how to decode the advertisement data sent by the Thermometer example taken from SDK v2. The first element is the flags byte which has same value as in first example. How advertising data is set? Let the stack fill the advertising data automatically, based on GATT content Application can set the advertising data content directly Option 1 is the simplest one.