====Bluetooth====

See [[interfaces:bluetooth]] for Linux Bluetooth devices and setup.

===Services===

Development has two service dependencies, dbus and bluetoothd.

==DBUS==

I normally disable dbus with systemd and here is how to enable this service with `runit' if preferred.

<code>
#!/bin/bash
sleep 1

#LOG
exec 2>&1
ulimit -aH

#RUN
export TZ="UTC"
rm -Rf /var/run/dbus
mkdir -p /var/run/dbus
exec dbus-daemon --syslog --syslog-only --nofork --config-file=/usr/share/dbus-1/system.conf
</code>

==BLUETOOTHD==

Install bluez and various tools if not already installed

<code>
apt install bluez bluez-tools bluez-test-tools bluez-hcidump
</code>

I prefer to run Bluetoothd from `runit'

This run file can work but it  should wait until dbus is ready before starting.

See the wait method of runit to detect /var/run/dbus/pid.

<code>
#!/bin/bash
sleep 5

#LOG
exec 2>&1
ulimit -aH

#RUN
export TZ="UTC"
exec /usr/sbin/bluetoothd -n
</code>

===C development===

Development in C is mostly about reading the code examples.

==Headers==

Install dev headers for the current installation of bluez

<code>
apt install libbluetooth-dev
</code>

==Source==
Access source code for documentation of how to use bluez

<code>
git clone https://github.com/bluez/bluez
</code>

bluez source code demonstrates how to access BT devices via dbus in the src directory or the API in the attrib and tools directories.

==Build==

Build the source to create tools

<code>
sudo apt-get install glib2.0-dev libdbus-1-dev libical-dev python3-docutils
./bootstrap
./configure --prefix=/opt/bt --enable-experimental --enable-deprecated
</code>

== Test==

Test [[:boards:wb15|STM32WB15CC]] BLE device.

<code>
./tools/btgatt-client -d 00:80:E1:22:F9:7C
Connecting to device... Done
[GATT client]# Service Added - UUID: 00001801-0000-1000-8000-00805f9b34fb start: 0x0001 end: 0x0004
[GATT client]# Service Added - UUID: 00001800-0000-1000-8000-00805f9b34fb start: 0x0005 end: 0x000b
[GATT client]# Service Added - UUID: 0000fe40-cc7a-482a-984a-7f2ed5b3e58f start: 0x000c end: 0x0011
[GATT client]# GATT discovery procedures complete
[GATT client]#
service - start: 0x0001, end: 0x0004, type: primary, uuid: 00001801-0000-1000-8000-00805f9b34fb
          charac - start: 0x0002, value: 0x0003, props: 0x20, ext_props: 0x0000, uuid: 00002a05-0000-1000-8000-00805f9b34fb
                  descr - handle: 0x0004, uuid: 00002902-0000-1000-8000-00805f9b34fb

service - start: 0x0005, end: 0x000b, type: primary, uuid: 00001800-0000-1000-8000-00805f9b34fb
          charac - start: 0x0006, value: 0x0007, props: 0x0a, ext_props: 0x0000, uuid: 00002a00-0000-1000-8000-00805f9b34fb
          charac - start: 0x0008, value: 0x0009, props: 0x02, ext_props: 0x0000, uuid: 00002a01-0000-1000-8000-00805f9b34fb
          charac - start: 0x000a, value: 0x000b, props: 0x02, ext_props: 0x0000, uuid: 00002a04-0000-1000-8000-00805f9b34fb

service - start: 0x000c, end: 0x0011, type: primary, uuid: 0000fe40-cc7a-482a-984a-7f2ed5b3e58f
          charac - start: 0x000d, value: 0x000e, props: 0x06, ext_props: 0x0000, uuid: 0000fe41-8e22-4541-9d4c-21edae82ed19
          charac - start: 0x000f, value: 0x0010, props: 0x10, ext_props: 0x0000, uuid: 0000fe42-8e22-4541-9d4c-21edae82ed19
                  descr - handle: 0x0011, uuid: 00002902-0000-1000-8000-00805f9b34fb

[GATT client]# ^C

Shutting down...
</code>

LED on/off for demo connection above.

<code>
[GATT client]# write-value -w 0x000E 0x01 0x01
Write command sent
[GATT client]# write-value -w 0x000E 0x01 0x00
Write command sent
[GATT client]#
</code>

===Python===

It's certainly a lot easier to write code to access BLE devices
in Python and preferred for demo purposes and maybe even
end use cases.

<code>
apt install python3-gattlib
</code>

Example for the [[:boards:wb15|STM32WB15CC]] BLE demo.

<code>
import sys, time

from gattlib import GATTRequester

req = GATTRequester("00:80:E1:22:F9:7C", False)

req.connect(True)

for n in range(10):
    req.write_cmd(0x000E, bytes([0x01,0x01]))
    time.sleep(1)
    req.write_cmd(0x000E, bytes([0x01,0x00]))
    time.sleep(1)

req.disconnect()
</code>