Introduction

A HCI interface can be implemented in lieu of smartBasic on IG60-LL. The benefit of making this change to the firmware is the ability to use the BL654 with standard tools such as bluetoothctl.

Prerequisites

For this project you will need:

  • IG60-LL that includes an internal BL654. The part numbers for this device are 455-00076 or 455-00088 (LTE)
  • MicroSD card to install Linux
  • Workstation with Linux installed
  • Network connection to the IG60 to copy files with SCP. By default, wired connections are configured for DHCP. To set a static address a serial connection is also required.
  • microSD card

Optional:

  • BT510 or other bluetooth device

Software Configuration

Provision microSD with Laird Linux

Build Laird Linux, or download and flash the prebuilt image from our GitHub repository:

https://github.com/LairdCP/IG60-Laird-Linux-Release-Packages/releases#flashing-a-developers-sd-card-image

Build or download hci_uart.hex

To build the hci_uart example for BL654_DVK, download the hci_uart sample found at:

https://docs.zephyrproject.org/latest/samples/bluetooth/hci_uart/README.html

Before compiling, set the offset for the bootloader.

vi samples/bluetooth/hci_uart/prj.conf

Add the following line:

CONFIG_FLASH_LOAD_OFFSET=0x1000

Compile the example. Use the -d switch to direct the output to a folder, for example:

west build -b bl654_dvk samples/bluetooth/hci_uart --pristine -d my_firmware

If you’re unable to compile, a pre-built zephyr.hex is included in the next section.

Download and copy these files to your IG60

The files below are contained in this repo in this zip file:

  • zephyr.hex
  • Ubutil_Linux_RPi
  • bl654_bl_util.py
  • btpa_firmware_loader.py #this file is already present in the default Laird Linux build in the /bin folder

Flashing the BL654

Add execute permissions.

chmod +x UBUtil_Linux_RPi

UBUtil is used to generate key pairs and firmware update images as follows:

./UBUtil_Linux_RPi --create-key hci_uart.pem

./UBUtil_Linux_RPi --application-key-file hci_uart.pem --a0-version 43 --a0-compressed --a0-target 0 --a0-startaddress 0x1000 --a0-filetype 1 --a0-filename  zephyr.hex --a0-keytype 1 --append-pub-key --output hci_uart.hex --ubu-output hci_uart.uwf --ubu-platform 5ECB654F --ubu-flash-size 2097152 --ubu-sector-size 4096 --ubu-base-address 0 --ubu-align-length 4

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Use the python script “bl654_bl_util.py” to erase the existing firmware and key.

python bl654_bl_util.py erase

Flash the signed firmware file to the BL654.

python btpa_firmware_loader.py /dev/ttyS2 115200 hci_uart.uwf

Verify the app version is “43”.

python bl654_bt_util version

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Starting the HCI interface and using Bluetoothctl

The final step is to create an HCI interface is to use btattach on the serial interface.

btattach -B /dev/ttyS2 -P h4 -S 115200 &

Verify there are two HCI interfaces.

ls /sys/class/bluetooth/

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Use Bluetoothctl to control the HCI and pair with a device.

bluetoothctl

In the bluetoothctl shell, list the interfaces.

list

The show command will show the attributes of each interface

show <mac>

Select the interface you wish to use.

select <mac>

Begin scanning.

scan on
scan off

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Display a list of detected devices.

devices

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Pair with your desired device.

pair <mac>
trust <mac>

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