Lesson 7 – WICED Bluetooth: Bluetooth Advertising

WICED Bluetooth Using the CYW20719

# Title Comment
0 A Two Hour WICED Bluetooth Class WICED Bluetooth Using the CYW20719 in all its glory
1 Resources Links to all of the Cypress WICED information including videos, application notes etc.
2 Your First Project Making Hello World & the Blinky LED
3 The Super Mux Tool Learning about platforms and the Super Mux Tool
4 Snips Using the example projects to learn Bluetooth
5 Bluetooth Designer Using the tool to customize a project and get going fast
6 The CCCD & Notification Writing back to the Central
7 Advertising  Beacon Building a beacon project to advertise your custom information 
8 Scanner Viewing the world around you
9 Bluetooth Classic SPP Using the Serial Port Profile to Transmit Lots of Data

Source code: 

  • git@github.com:iotexpert/wiced_bt_intro.git
  • https://github.com/iotexpert/wiced_bt_intro

 

Summary

Everywhere you go there are bunches of Bluetooth devices that are acting as beacons.  Apple has a standard called iBeacon.  Google has a standard called Eddystone.  Some companies use those standards, and some companies make proprietary beacons.  In this lesson we will build a beacon.

The important concepts in this lesson are:

  1. Advertising packet formats
  2. wiced_bt_cfg.c

The steps I will follow are:

  1. Run BT Designer
  2. Setup the device as “no gatt database”
  3. Move the project into the wiced_bt_class folder
  4. Edit the make target
  5. Fix the WICED_BT_TRACE to go to the PUART
  6. Run it
  7. Edit the wiced_bt_cfg.c to never timeout
  8. Setup no random address changing
  9. Add the manufacturing data uint8_t array and include the Cypress company code
  10. Change the start advertising call to BTM_BLE_ADVERT_NONCONN_HIGH, BLE_ADDR_PUBLIC
  11. Update the length of the advertising packet
  12. Update the set advertising packet to have the manufacturing data
  13. Add a button interrupt function
  14. Register the button interrupt

BLE Concepts

The Advertising Packet is a string of 3-31 bytes that is broadcast at a configurable interval. The packet is broken up into variable length fields. Each field has the form:

  • Length in bytes (not including the Length byte)
  • Type
  • Optional Data

The minimum packet requires the <<Flags>> field which is a set of flags that defines how the device behaves (e.g. is it connectable?). Here is a list of the other field Types that you can add:

Here is an example of the advertising packet that we are going to generate

Implement the Project

Run BT Designer and create a new project called “L7_Advertising”

Turn off the GATT Database

Move the project into the wiced_bt_class folder

Edit the make target

Setup the the WICED_BT_TRACE to use the PUART

Run it

Now that we know it is working, Ill edit the wiced_bt_cfg.c to never timeout

Setup no random address changing

Now edit the L7_Advertising.c to add the manufacturing data uint8_t array

Switch to non-connectable advertising

Update the l7_advertising_set_advertisement_data function to have three elements in the advertising packet

Add the Manufacturer information to the advertising packet

Add a button interrupt function

Register the button interrupt

Test using the AdvScanner

I have given you a project called the “AdvScanner”.  You can run it by creating a make target.

When I run the L7_Advertising project and press the buttons a few times my terminal will look like this

And when I look at the output of the scanner program you can see the advertising packet for the this project.  Notice that the last three bytes are 31 01 03.  The 03 is the count of button presses.