5.1.2.3 BLE Extended Advertisements

This section explains how to enable Extended Advertisements (1M, 2M, Coded PHY - 125 kbps) on the PIC32-BZ6 Curiosity Board. This example demonstrates how users can send application data using extended advertisements.

Extended Advertisements allow more data to be transmitted than legacy advertisements and support long-range functionality using Coded PHY. Use of Extended Advertisements also enables the users to select between different PHYs (1M, 2M and LE Coded) which are not permitted with legacy advertisements. In BLE, a peripheral or broadcaster always initiates communication using advertisements. These advertisement packets enable a central or observer to discover a peripheral or broadcaster.

This example uses Extended Advertisements for either transmitting more data (2M PHY) or conducting range tests (Coded PHY). For testing these features, a scanner application can be used which is configured to scan the extended advertisement packets.

Users can choose to either run the precompiled Application Example hex file provided on the PIC32-BZ6 Curiosity Board or follow the steps to develop the application from scratch.

These examples build upon one another. It is recommended to follow the examples in sequence to understand the basic concepts before progressing to the advanced topics.

Recommended Readings

  1. Getting Started with Application Building Blocks – See Building Block Examples from Related Links.

  2. Getting Started with Peripheral Building Blocks – See Peripheral Devices from Related Links.

  3. BLE Software Specification – See MPLAB® Harmony Wireless BLE in Reference Documentation from Related Links.

  4. FreeRTOS and BLE Stack Setup – See Peripheral - FreeRTOS BLE Stack and App Initialize from Related Links.

Hardware Requirement

Table 5-14. Hardware Prerequisites
S. No. Tool Quantity
1PIC32-BZ6 Curiosity Board1 (2 if testing with a scanner)
2Micro USB cable1
3Android/iOS Smartphone1
4(Optional) Power Debugger(1)/Multimeter/Oscilloscope to measure power
Note:
  1. For more information, refer to Power Debugger in Reference Documentation from Related Links.
1

SDK Setup

Refer to Getting Started with Software Development from Related Links.

Software Requirement

To install Tera Term tool, refer to the Tera Term web page in the Reference Documentation from Related Links.

Smartphone App

None

Programming the Precompiled Hex File or Application Example

Using MPLAB® X IPE:

  1. Import and program the precompiled hex file: <Harmony Content Path>\wireless_apps_pic32_bz6\apps\ble\building_blocks\peripheral\ext_adv\precompiled_hex\ext_adv.X.production.signed.hex.

  2. For detailed steps, refer to Programming a Device in MPLAB® IPE in Reference Documentation from Related Links.

    Note: Ensure to choose the correct Device and Tool information.

Using MPLAB® X IDE:

  1. Perform the following the steps mentioned in Running a Precompiled Example. For more information, refer to Running a Precompiled Application Example from Related Links.

  2. Open and program the application: <Harmony Content Path>\wireless_apps_pic32_bz6\apps\ble\building_blocks\peripheral\ ext_adv\firmware\ext_adv.X.

  3. For more details on how to find the Harmony Content Path, refer to Installing the MCC Plugin from Related Links.

Demo Description

This application example transmits Extended Advertisements using the Coded PHY at a data rate of 125 kbps. PDU types of ADV_AUX_IND and ADV_EXT_IND will be transmitted.
  • Application data (“Microchip”) is transmitted in Auxiliary packets (ADV_AUX_IND).
  • ADV_EXT_IND carries the auxiliary packet information (ADV_AUX_IND) for the scanner to collect the data.

The message “Ext Adv Enabled” will be printed on Tera Term, indicating successful start of Coded PHY Advertisements. Coded PHY Advertisements are configured to be sent every 2 seconds.

Note:

BLE Extended Advertisements typically cannot be scanned using a smartphone app. This could be due to support of only legacy advertisements on the smartphone or the disabled extended advertisement APIs in the smartphone app.

Testing

  1. Using a micro USB cable, connect the Debug USB on the Curiosity boards to a PC.
  2. Program the precompiled hex files or application examples:
    1. Board1: PIC32-BZ6 Curiosity Board with BLE Ext Adv Programmed
    2. Board2: PIC32-BZ6 Curiosity Board with BLE Scan Ext Adv Programmed, see BLE Scanning Extended Advertisements from Related Links.
  3. Open Tera Term for each board:
    • Set Serial Port to USB Serial Device.
    • Set Speed to 115200.
    • Reset the boards
    • Board 1 will display “Ext Adv Enabled”.
    • Board 2 will display “ExtAdv Scan Enable Success”, followed by “Microchip” as soon the PIC32WM-BZ6204UE module performs an extended advertisement scan.

    For more details on how to set the “Serial Port” and “Speed”, refer to COM Port Setup in Running a Precompiled Application Example from Related Links.

Developing this Application from Scratch using MPLAB Code Configurator

Follow the steps below to build the application manually:
Note: It is recommended for the new users of the MPLAB Code Configurator to refer MPLAB® Code Configurator (MCC) User’s Guide in Reference Documentation from Related Links.

  1. Create a new harmony project. For more details, see Creating a New MCC Harmony Project from Related Links.

  2. Setup the basic components and configuration required to develop this application, import component configuration: <Harmony Content Path>\wireless_apps_pic32_bz6\apps\ble\building_blocks\peripheral\ext_adv\firmware\ext_adv.X\ext_adv.mc3.
    Note: Import and Export functionality of the Harmony component configuration will help users to start from a known working setup of the MCC configuration.
  3. Accept dependencies or satisfiers when prompted.
  4. Verify if the Project Graph window has all the expected configuration.
    Figure 5-80. Project Graph

Verify Advertisement Configuration

  1. Select the BLE Stack component in the Project Graph.
  2. Configure Extended Advertisements in the Configuration Options panel as shown in the following image.

Configuring UART

For more details on UART Configuration, refer to csp_apps_pic32cxbz6_wmbz6/apps/sercom/usart/ application examples.

Generating Code

For more details on code generation, refer to MPLAB Code Configurator (MCC) Code Generation from Related Links.

Files and Routines Automatically Generated by the MCC

After generating the program source from the MCC interface (by clicking Generate Code), the BLE configuration source and header files can then be found in the following project directories.

Initialization routines for OSAL, RF System, and BLE System are auto-generated by the MCC. See OSAL Libraries Help in Reference Documentation from Related Links. Initialization routine executed during program initialization can be found in the project file.

The BLE stack initialization routine executed during Application Initialization can be found in project files. This initialization routine is automatically generated by the MCC. This call initializes and configures the GAP, GATT, SMP, L2CAP and BLE middleware layers.

Autogenerated Advertisement Data Format

Table 5-15. Source Files
Source Files Usage
app.cApplication State machine, includes calls for Initialization of all BLE stack (GAP,GATT, SMP, L2CAP) related component configurations
app_ble\app_ble.cSource code for the BLE stack related component configurations, code related to function calls from app.c
app_ble\app_ble_handler.cGAP, GATT, SMP and L2CAP event handlers
app_user_edits.cUser code change instructions
Note: app.c is autogenerated and has a state machine-based application code sample. Users can use this template to develop their own application.

Header Files

  • ble_gap.h contains BLE GAP functions and is automatically included in app.c

Function Calls

  • MCC generates and adds the code to initialize the BLE Stack GAP, GATT, SMP and L2CAP in APP_BleStackInit()
  • APP_BleStackInit() API is called in the Applications Initial State APP_STATE_INIT in app.c
  • RTC_Timer32Start() defined in plib_rtc_timer.c calls to start the RTC Timer clock to facilitate low power mode

User Application Development

Include

  • Include the user action. For more information, refer to User Action from Related Links.
  • definitions.h must be included in all the files, where UART will be used to print debug information.
    Note: definitions.h is not specific to UART but instead must be included in all the application source files where any peripheral functionality will be exercised.
Starting Extended Advertisement in app.c.
BLE_GAP_SetExtAdvEnable(true, 0x01, &extAdvEnableParam);

This API is called in the applications initial state APP_STATE_INIT in app.c. Parameters for the extended advertisement must be configured appropriately. The following image is an example.

Note: Users can explore more BLE Advertisement functionalities using the BLE Stack APIs. For more information, refer to BLE Stack in Reference Documentation from Related Links.

Where to Go from Here

Getting Started with Peripheral Building Blocks – See Peripheral Devices from Related Links.