1. STM32WBA Long Range
Long range or LE coded feature is a way to extend BLE range up to 1,6 km or more.
Using advertising extension feature is the way to activate LE coded advertising Primary (and secondary) PHY as LE coded. New parameters values are defined in HCI and ACI commands.
Based on BLE_p2pClient_Ext and BLE_p2pServer_Ext applications, two new applications have been developed to demonstrate the feature and to provide range measurements: BLE_App_Long_Range_Central and BLE_App_Long_Range_Peripheral.
Applications functionalities are derived from BLE_p2pClient and BLE_p2pServer applications:
Refer to the following page for Peer to Peer project explanation.
1.1. Principles
Advertising extension feature is necessary.
Modified or new GAP commands have been implemented to enable LE coded feature.
- To set advertising parameters:
aci_gap_adv_set_configuration: Adv_Mode parameter: 0x02: use LE coded as primary advertising PHY.
- Scan procedure:
aci_gap_ext_start_scan: scanning_PHY parameter: 0x04: use of LE coded as scan PHY.
- Connection:
aci_gap_ext_create_connection: initiating PHYs parameter: 0x04: use of LE coded as scan connectable PHY.
1.2. Advertising data
At startup, Peer To Peer Server application starts Advertising.
Data advertised are composed as follows:
P2P Server Long Range Advertising packet | ||||||||||||||||
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Manufacturer data are encoded following STMicroelectronics BlueST SDK v2 as described below:
STMicroelectronics Manufacturer Advertising data | |||||||||||||||||||||||||||||||||
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1.3. STM32WBA Long Range Central and Peripheral application
Long Range Central acts as a Central device with the support of GATT Client Layer.
At startup, by pressing B1 button, Long Range Client application:
- Starts scanning to detect Long Range Server application by filtering the Firmware ID of the STMicroelectronics Manufacturer advertising data
- Stops Scanning once Long Range server detected
- Connects to the Long Range Server to establish the connection.
- Discovers GATT Service & Characteristics of the Long Range server
- Enable all GATT server notification characteristics
Once connected, the Long Range Client application:
- By pressing B1 button, write a message to toggle the Blue LED of the Long Range Server
- Receive notification to toggle the on board Blue LED from remote Long Range Server Application.
Long Range Peripheral acts as a Periphera ldevice with the support of GATT Client Layer.
At reset, Long Range Peripheral application starts one extended advertising set at primary and secondary LE coded PHY.
Once connected, on both applications:
- By pressing B2 button, HCI_LE_SET_PHY command is sent. It allows to toggle Phy_options parameter S=8/2 (red led is ON/OFF)
Example of flow diagram between STM32WBA Long Range Server & Long Range Client |
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B2 to toggle Phy options S=2, S=8 |
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1.4. On-board buttons configuration
Button configuration for Bluetooth® Low Energy Long Range application on Nucleo-WBA52CG boards | ||||||||||||||||||||||||
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1.5. Collector applications compatibility
The BLE_App_Long_Range_Peripheral project is compatible with the following collector:
1.6. Code example
A STM32WBA Long Range code example has been shared on STM32-Hotspot GitHub [1]