4.1.2.3 BLE Extended Advertisements

Introduction

This document will help users enable Extended Advertisements (1M, 2M, coded PHY -- 125kbps) on WBZ351 Curiosity Board. This example (ext_adv) enables users to send application data using extended advertisements. Extended Advertisements are used to send more data than the legacy advertisements allow and allow long range functionality when 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 when using legacy advertisements. In BLE a peripheral or broadcaster always starts with advertisements. Advertisement packets enable a central or observer to discover a peripheral or broadcaster.

Extended Advertisements implemented in this example can be used for sending more data (2M PHY) or do range tests (Coded PHY). For testing these features a scanner Application can be used which is configured to scan the extended advertisement packets.

To save power, low power mode can be enabled. If conditions are met then WBZ351 will enter into sleep mode. The following sections discuss it in details.

Users can run the precompiled Application Example hex file provided with this example on the WBZ351 Curiosity Board and go through the steps involved in developing this Application application from the scratch

These examples each build on top on one and other. We strongly recommend that you follow the examples in order, to learn the basics concepts before progressing to the more advanced topics.

Hardware Requirement


Tool	Qty
WBZ351 Curiosity Board	1 (2 if testing with a scanner)
Micro USB cable	1

Optional Power Debugger/Multimeter/OscilloScope to measure power.

SDK Setup

Getting Started with Software Development

Software Requirement

TeraTerm

Smartphone App

None

Programming the Precompiled Hex File or Application Example

Programming the hex file using MPLABX IPE

Precompiled Hex file is located in"<Harmony Content Path>\wireless_apps_pic32cxbz3_wbz35\apps\ble\building_blocks\peripheral\ext_adv\hex" folder
For more details on the steps, go to Programming A Device .
Note: Ensure to choose the correct Device and Tool information.

Programming the Application using MPLABX IDE

Follow steps mentioned in of Running a Precompiled Example document
Open and program the Application Example "ext_adv.x" located in"<Harmony Content Path>\wireless_apps_pic32cxbz3_wbz35\apps\ble\building_blocks\peripheral\ext_adv\firmware" using MPLABX IDE

For more details on how to find the Harmony Content Path, refer to Installing the MCC Plugin

Demo Description

This Application Example enables users to transmit Extended Advertisements @ Coded PHY data rate of 125 Kbps. PDU types of ADV_EXT_IND and ADV_AUX_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 scanner to collect the data.

Demo will print "Ext Adv Enabled" information indicating the successful start of Coded PHY Advertisements on a terminal emulator like TeraTerm @ (Speed: 115200, Data: 8-bit, Parity: none, stop bits: 1 bit, Flow control: none). Coded PHY Advertisements are configured to be sent every 2 secs.

BLE Extended Advertisements (125 kbps, 500 kbps)cannot be scanned using a smartphone app. This could be due to support of only legacy advertisements on the smartphone or disabled extended adv API's in smartphone app.

Testing

Users can use another WBZ351 Curiosity Board configured as BLE Scan Ext Adv

This section assumes that a user has already programmed the ext_adv and scan_ext_adv application on 2 WBZ351 Curiosity Boards.

Board1: WBZ351 Curiosity Board with Ext Adv Programmed

Board2: WBZ351 Curiosity Board with Scan Ext Adv Programmed

Board1: Open TeraTerm @ (Speed: 115200, Data: 8-bit, Parity: none, stop bits: 1 bit, Flow control: none). Reset the board. Upon reset, "Ext Adv Enable" message is displayed on the TeraTerm.

Board2: Open TeraTerm @ (Speed: 115200, Data: 8-bit, Parity: none, stop bits: 1 bit, Flow control: none). Reset the board. Upon reset, "ExtAdv Scan Enable Success" message is displayed on the TeraTerm. "Microchip" message will be displayed as soon the WBZ351 module performs an extended advertisement scan.

Current Consumption Measurement

Connect the Multimeter/Power Debugger/Oscillo Scope to Power Measurement Header J6. If using Power Debugger, users can use Data Visualizer to measure the current consumption. Current measured in sleep/standby mode is 575.6 uA and avg current consumption is around 723.0 uA

Users of this package should go through the known issues document and understand the limitations if any with the current low power mode implementation.

Developing this Application from Scratch using MPLAB Code Configurator

This section explains the steps required by a user to develop this application example from scratch using MPLABx Code Configurator

Note: It is recommended that new users of MPLAB Code Configurator go through the overview.

Setup Harmony framework. EA release package has all the neccessary component and should be downloaded individually from the link provided in the package. It is recommended to create framework in the root directory. The framework looks like:
Create a new MCC Harmony Project. For more details on creating a new MCC Harmony Project, refer to 3.4 Creating a New MCC Harmony Project .
Drag and drop BLE_Stack in the project graph and select Yes to all pop ups. Drag and Drop SERCOM0 from Peripherals into project graph for UART messages. Project Graph will look like
Enable Low Power

– Enable Low power mode by selecting Low Power Enable in BLE_Stack Configuration. Select Yes to all pop ups

Click on Window->MCC->Harmony->Clock Configuration

Advertisement Configuration

Select BLE_Stack component in project graph and make modifications as shown below

Configuring UART

For more details on UART Configuration, refer to UART Hello World

Generating a Code

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

Files and Routines Automatically Generated by the MCC

After generating the program source from MCC interface by clicking Generate Code, the BLE configuration can be found in the following project directories

The OSAL , RF System, BLE System initialization routine executed during program initialization can be found in the project files. This initialization routine is automatically generated by the MCC

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

Autogenerated, extended adverisement Data Format


Source Files	Usage
`app.c`	Application State machine, includes calls for Initialization of all BLE stack (GAP,GATT, SMP, L2CAP) related component configurations
`app_ble\app_ble.c`	Source Code for the BLE stack related component configurations, code related to function calls from app.c
`app_ble\app_ble_handler.c`	All GAP, GATT, SMP and L2CAP Event handlers
`app_user_edits.c`	User Code Change instruction

Note: app.c is auto generated and has a state machine based Application code sample and users can use this template to develop the application|

Header Files

ble_gap.h: This header file contains BLE GAP functions and is automatically included in the app.c file

Function Calls

MCC generates and adds the code to initialize the BLE Stack GAP, GATT, L2CAP and SMP in APP_BleStackInit() function

APP_BleStackInit() is the API that will be called inside the Applications Initial State -- APP_STATE_INIT in app.c
RTC_Timer32Start() defined in plib_rtc_timer.c. It call to start RTC Timer clock to facilitate low Power mode.

User Application Development

Include

definitions.h in all the files where UART will be used to print debug information
Note: definitions.h is not specific to just UART peripheral, instead it should be included in all application source files where peripheral functionality will be exercised

User action is required as mentioned in User Action

Start Ext Advertisement

BLE_GAP_SetExtAdvEnable(true, 0x01, &extAdvEnableParam);

This API is called in the Applications initialstate - APP_STATE_INIT in app.c. Parameters for extended advertisement should be chosen. Below is an example.