5.1.1.2 BLE Legacy Scan

Recommended Readings

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

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

3. FreeRTOS and BLE Stack Setup – See Central - FreeRTOS BLE Stack and App Initialize from Related Links.

4. See BLE Legacy Scan from Related Links.
5. See BLE Connection from Related Links.

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

Hardware Requirement

SDK Setup

Software

1. To install Tera Term tool, refer to the Tera Term web page in 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\central\legacy_scan\precompiled_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: legacy_scan.X located in <Harmony Content Path>\wireless_apps_pic32_bz6\apps\ble\building_blocks\central\legacy_scan\firmware.

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 enables users to do passive scanning. After programming the application example, on Reset user will be able to see the beginning of scan operation, The Bluetooth addresses of devices will be scanned for the next 10 seconds. After 10 seconds the scanning operation will complete.

Testing

Users can use another PIC32-BZ6 Curiosity Board configured as BLE Legacy Advertisements set the address and scan. For more information, refer to BLE Legacy Advertisements from Related Links.

Developing this Application from Scratch Using MCC

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

2. Import component configuration -This step helps users setup the basic components and configuration required to develop this application. The imported file is of format .mc3 and is located in the path <Harmony Content Path>\wireless_apps_pic32_bz6\apps\ble\building_blocks\central\legacy_scan\firmware\legacy_scan.X..

3. Accept dependencies or satisfiers when prompted.

4. Verify if the project graph window has all the expected configuration.

   

Verifying the Scan Configuration

1. Click on the BLE Stack component in project graph, to open component configuration and configure as illustrated in the following figure.

   

Generating a 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 MCC interface by clicking Generate Code, the BLE configuration can 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 files.

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

Note: app.c is autogenerated and has a state machine based application code sample, users can use this template to develop their 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 initialization state APP_STATE_INIT in app.c

User Application Development

Include

• Include the user action. For more information, refer to User Action from Related Links.
• 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 must be included in all application source files where peripheral functionality will be exercised.

Start Scanning

// Scanning Enabled
BLE_GAP_SetScanningEnable(true, BLE_GAP_SCAN_FD_ENABLE, BLE_GAP_SCAN_MODE_OBSERVER, 100);
// Output the status string to UART
SERCOM0_USART_Write((uint8_t *)"Scanning \r\n", 11);

This API is called in the application’s initialization state - APP_STATE_INIT in app.c. Scan duration is 10 seconds.

Scan Results

• BLE_GAP_EVT_ADV_REPORT event is generated upon finding advertisements on legacy channels.

  // code snippet to print scan results
  uint8_t scanAddr[12]; //var to store ASCII address
  BLE_GAP_EvtAdvReport_T scanResults;
  scanResults.addr = p_event->eventField.evtAdvReport.addr;
  APP_HexToAscii(6, scanResults.addr.addr, scanAddr);
  SERCOM0_USART_Write((uint8_t *)"0x", 2);
  SERCOM0_USART_Write((uint8_t *)scanAddr, 12);
  SERCOM0_USART_Write((uint8_t *)"\r\n", 2);

// function to convert HEX to ASCII
static void APP_HexToAscii(uint8_t byteNum, uint8_t *p_hex, uint8_t *p_ascii)
{
    uint8_t i, j, c;
    uint8_t digitNum = byteNum * 2;

    if (p_hex == NULL || p_ascii == NULL)
        return;

    for (i = 0; i < digitNum; i++)
    {
        j = i / 2;
        c = p_hex[j] & 0x0F;

        if (c >= 0x00 && c <= 0x09)
        {
            p_ascii[digitNum - i - 1] = c + 0x30;
        }
        else if (c >= 0x0A && c <= 0x0F)
        {
            p_ascii[digitNum - i - 1] = c - 0x0A + 'A';
        }

        p_hex[j] /= 16;
    }
}

Add the above code to the appropriate sections within the app_ble_handler.c.

Scan Timeout Event

• In app_ble_handler.c, BLE_GAP_EVT_SCAN_TIMEOUT event is generated when BLE Scan duration expires.

  • Add the following code, inside BLE_GAP_EVT_SCAN_TIMEOUT case.

    SERCOM0_USART_Write((uint8_t *)”Scan Completed \r\n”, 17);

  

Where to Go from Here

See BLE Connection from Related Links.