1. Introduction
The transparent mode application is used to:
- receive commands on UART RX and propagate them to the Bluetooth® Low Energy stack.
- transmit events from Bluetooth®Low Energy stack on UART TX.
A set of commands/events are sent though the STM32WBA UART to control the Bluetooth® Low Energy stack via the transparent mode application.
Level shifter, VCP ST-LINK or applicative VCP can be used to manage transmission and reception.
Transparent mode with NUCLEO-WBA52CG board and ST-LINK VCP |
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2. Requirements
2.1. Software and system requirements
Below the required software as well as the required minimum IDE version:
- IAR Embedded Workbench for ARM (EWARM) toolchain V9.20.1, plus a patch available in STM32CubeWBA MCU package: STM32Cube_FW_WBA_Vx.x.x/Utilities/PC_Software/EWARMv8_STM32WBAx_V1.2.zip
- RealView Microcontroller Development Kit (MDK-ARM) toolchain V5.37, plus a patch available in STM32CubeWBA MCU package: STM32Cube_FW_WBA_Vx.x.x/Utilities/PC_Software/Keil.STM32WBAx_DFP.1.0.0.zip
- STM32CubeIDE toolchain V1.12.0 [1].
The following programmer software is required to flash the board with an already generated binary:
- STM32CubeProgrammer[2]
To interface with transparent mode application, STM32CubeMonitor-RF software is also required:
- STM32CubeMonitor-RF V2.11.0 [3]
2.2. Hardware requirements
The application must be installed on the NUCLEO-WBA52CG [4].
Hardware platform illustration |
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3. Transparent mode example description
3.1. Project directory
The "BLE_TransparentMode" application is available by downloading STM32CubeWBA MCU Package[5].
Refer to How to Build a Bluetooth® LE project wiki page for project directory information.
3.2. Project description
3.2.1. Software project structure
Below the software project structure with the main parts:
Transparent Mode project structure |
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WARNING: Do not modify the files in Middlewares folder |
3.2.2. Bluetooth® Low Energy host stack
The transparent mode application uses the Full host stack + ST LL controller library (stm32wba_ble_stack_full.a), which requires LinkLayer_BLE_Full_lib.a to work.
Refer to Bluetooth_LE_Host_Stack_and_Link_Layer_Libraries_compatibilities section.
This configuration supports all the available ACI and HCI commands, as well as Bluetooth® Low Energy features.
More information about the Bluetooth® Low Energy host stack library and the different Bluetooth® Low Energy stack configurations for STM32WBA projects are available in: Middlewares/ST/STM32_WPAN/ble/stack/doc/STM32WBA_BLE_Stack_User_Manual.html.
3.2.3. Application initialization
The different steps of the application initialization are described below:
Transparent mode project initialization |
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3.3. Build and install
Follow the steps described in Bluetooth® LE Build and Install Application page, applying them for STM32WBA BLE_TransparentMode project.
3.4. How to use the Bluetooth® Low Energy Transparent Mode application
Once the Bluetooth® Low Energy Transparent Mode application is installed on the STM32WBA platform, launch STM32CubeMonitor-RF [3] application on the computer connected to the WBA platform via USB.
3.4.1. STM32CubeMonitor-RF interface
On STM32CubeMonitor-RF interface, select the COM port of the WBA nucleo platform and click on CONNECT button:
STM32CubeMonitor-RF connection with Transparent Mode |
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Platform and SW information can be found in VS_HCI_C1_DEVICE_INFORMATION answer:
STM32CubeMonitor-RF device information |
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ACI Utilities allows user to easily launch Advertising or Scan Sequence:
STM32CubeMonitor-RF Advertising and Scan Sequences |
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3.4.2. Vendor Specific Commands
Vendor specific commands have been developed to Read device information, Read and Write registers from command interface:
- VS_HCI_C1_DEVICE_INFORMATION
- VS_HCI_C1_WRITE_REGISTER
- VS_HCI_C1_READ_REGISTER
Transparent Mode Vendor Specific Commands | ||||
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Command Name | HCI packet indicator | OCF | Description | Parameter |
VS_HCI_C1_WRITE_REGISTER | 0x20 | 0x160 | Request core to write a register (Atomic write) |
1byte [0]: Bus size access - 1 : 8bits - 2 : 16bits - 4 : 32bits 4bytes [1:4]: Mask 4byte [5:8]: Address 4byte [9:12]: Value |
VS_HCI_C1_READ_REGISTER | 0x20 | 0x161 | Request core to read a register (Atomic read) |
1byte [0]: Bus size access - 1 : 8bits - 2 : 16bits - 4 : 32bits 4bytes [1:4]: Address |
VS_HCI_C1_DEVICE_INFORMATION | 0x20 | 0x162 | Return device information | N/A |
4. References