6.1 Provisioning through Bluetooth® LE - Protocol Exchange

Protocol Exchange

This section explains the communication protocol exchange between Bluetooth LE Provisioner mobile app/ Bluetooth LE sensor mobile app (Bluetooth LE central) and PIC32 BZ6 Module (Bluetooth LE peripheral).

• Advertisement Data:

  • Service UUID: 16-bit Service UUID, 0xFEDA is purchased by Microchip from Bluetooth SIG.

  • Other Info: 0x40+Light ON/Off status (1 Byte)+ 0x41+Temperature data (2 bytes)

• Scan Response Data:

  • The device name is part of the scan response. Device name is set as "COMBO_LIGHT_XXXX” by default (XXXX means the last two bytes of the device address). This device name can be changed using "Bluetooth LE Provisioner" app as described in demo step #5

Transparent Profile and Service (TRP/TRS) is the proprietary Bluetooth LE service by microchip to establish data and control channel between Bluetooth LE Central (Phone) and Peripheral (device).

• Transparent Profile (TRP) enables higher layer application to control and allow data exchange between TRP Client and Server devices

• Transparent Service (TRS) includes both Ctrl and Data Pipes which are custom 128-bit GATT characteristics.

  • The Transparent Server shall be a GATT Server

  • The Transparent Client shall be a GATT Client

BLE Sensor and BLE Provisioner application over Transparent Service Control Point (TRS Ctrl Pt):

The combo application uses TRS Control Point Characteristic of TRPS profile to exchange data between "BLE Sensor" and "BLE Provisioner" mobile app and device.

The combo application follows the below protocol format on TRS control point characteristic.

The description of each element is as below:

- The Opcode:
   - (0x81) is fixed 1 byte in size and related to Provisioning commands.
   - (0x8A) is fixed 1 byte in size and related to BLE Sensor/Control commands
- Length: 1 byte in size (size of Sensor/Control ID + size of Payload)
- The Sensor/Control ID: 1 byte in size. It could be divided into Control request, Control response, Sensor/Provisioning notify data described in detail in following sections.
- The Sensor/Provisioning/control data and payload size depends on the ID as listed in the below table.

Control Command Request and Response

The Control command request is used by mobile app to send the command to device. The control request channel is opened only after Client Characteristic Configuration Descriptor of TRS Ctrl Pt Characteristic notification is enabled; it is closed when such notification is disabled.

The format of Control command is an 8bit Opcode, an 8bit request ID followed by optional control payload.

The control response is used by the device to send feedback to mobile app. The format of Response is an 8bit Opcode, an 8bit response ID and response status followed by optional Response payload.

Status code 0x00 means successful execution of control command. Any status code other than 0x00 means error code, as shown in below Table. An error status does not have optional control Response payload.

Sensor/Provisioning Notify Data

The Sensor data is sent to mobile app periodically by PIC32 BZ6 device. Similarly the commissioning status is sent to "BLE provisioner" during the commissioning procedure. The data channel is opened only after Client Characteristic Configuration Descriptor of TRS Ctrl Pt notification is enabled; it is closed when such notification is disabled.

The format of sensor data is an 8 bit Opcode, an 8bit ID followed by notify data payload.