Bluetooth¶

EC-A1684JD4 supports wireless bluetooth, you can display the bluetooth device information through hciconfig -a command:

linaro@bm1684:~$ hciconfig -a
hci0:	Type: Primary  Bus: USB
	BD Address: 20:57:9E:BA:7C:EC  ACL MTU: 1021:8  SCO MTU: 255:16
	UP RUNNING 
	RX bytes:650 acl:0 sco:0 events:41 errors:0
	TX bytes:2170 acl:0 sco:0 commands:41 errors:0
	Features: 0xff 0xff 0xff 0xfa 0xdb 0xbd 0x7b 0x87
	Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
	Link policy: RSWITCH HOLD SNIFF PARK 
	Link mode: SLAVE ACCEPT 
	Name: 'bm1684'
	Class: 0x000000
	Service Classes: Unspecified
	Device Class: Miscellaneous, 
	HCI Version: 4.2 (0x8)  Revision: 0xaba8
	LMP Version: 4.2 (0x8)  Subversion: 0xa0cd
	Manufacturer: Realtek Semiconductor Corporation (93)

Note that if the following error message is printed:

Can't open HCI socket.: Address family not supported by protocol

Then there may be a problem with the dependencies of the loadable modules. At this time, reload the dependencies and soft restart:

sudo -i
depmod -a
reboot

Check whether it is currently the master device or the slave device:

linaro@bm1684:~$ hciconfig hci0 lm
hci0:	Type: Primary  Bus: USB
	BD Address: 20:57:9E:BA:7C:EC  ACL MTU: 1021:8  SCO MTU: 255:16
	Link mode: SLAVE ACCEPT # slave device

Start the PulseAudio service as a media device:

linaro@bm1684:~$ pulseaudio --start --log-target=syslog

The steps to connect a Bluetooth device are as follows:

(1) Start the Bluetooth controller tool:

linaro@bm1684:~$ bluetoothctl
[NEW] Controller 20:57:9E:BA:7C:EC bm1684 [default]

(2) Power on the Bluetooth controller:

[bluetooth]# power on
Changing power on succeeded

(3) Set the bluetooth agent as default:

[bluetooth]# agent on
Agent registered
[bluetooth]# default-agent
Default agent request successful

(4) Open to be discovered by other Bluetooth devices:

[bluetooth]# discoverable on
Changing discoverable on succeeded
[CHG] Controller 20:57:9E:BA:7C:EC Discoverable: yes

(5) At this point, the EC-A1684JD4 Bluetooth device can be found on the smartphone, and the phone can be paired after clicking:

[NEW] Device A4:90:CE:DF:64:4F iQOO Neo6 SE
[CHG] Device A4:90:CE:DF:64:4F Modalias: bluetooth:v001Dp1200d1436
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001105-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 0000110a-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001112-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001115-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001116-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 0000111f-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 0000112d-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 0000112f-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001132-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001800-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 00001801-0000-1000-8000-00805f9b34fb
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 2c042b0a-7f57-4c0a-afcf-1762af70257c
[CHG] Device A4:90:CE:DF:64:4F UUIDs: 8fa9c715-bd1f-596c-a1b0-13162b15c892
[CHG] Device A4:90:CE:DF:64:4F ServicesResolved: yes
[CHG] Device A4:90:CE:DF:64:4F Paired: yes
[CHG] Device A4:90:CE:DF:64:4F ServicesResolved: no
[CHG] Device A4:90:CE:DF:64:4F Connected: no
[CHG] Controller 20:57:9E:BA:7C:EC Discoverable: no

(6) Connect mobile device:

[bluetooth]# connect A4:90:CE:DF:64:4F
Attempting to connect to A4:90:CE:DF:64:4F
[CHG] Device A4:90:CE:DF:64:4F Connected: yes
Connection successful
[CHG] Device A4:90:CE:DF:64:4F ServicesResolved: yes
[iQOO Neo6 SE]# 

(7) Set the mobile device to trust:

[iQOO Neo6 SE]# trust A4:90:CE:DF:64:4F
[CHG] Device A4:90:CE:DF:64:4F Trusted: yes
Changing A4:90:CE:DF:64:4F trust succeeded

Bluetooth Audio¶

Update resource¶

Add the new resource list to the /etc/apt/sources.list：

deb-src https://mirrors.huaweicloud.com/ubuntu-ports/ bionic main restricted universe multiverse
deb-src https://mirrors.huaweicloud.com/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb-src https://mirrors.huaweicloud.com/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb-src https://mirrors.huaweicloud.com/ubuntu-ports/ bionic-security main restricted universe multiverse

Update：

apt-get update

Compile and install sbc 1.5-3¶

# clone and checkout
git clone https://salsa.debian.org/bluetooth-team/sbc.git
cd sbc
git checkout debian/1.5-3

# downgrade debhelper-compat
sed -i -e 's/debhelper-compat (= 13)/debhelper-compat (= 12)/g' debian/control

# install build dependency
sudo apt-get build-dep sbc

# build deb
dpkg-buildpackage -b -us -uc

# install deb
cd ..
sudo apt-get install ./*sbc*_1.5-3_*.deb

Compile and install fdk-aac 2.0.2¶

# clone and checkout
git clone https://salsa.debian.org/multimedia-team/fdk-aac
cd fdk-aac
git checkout debian/2.0.2-1

# downgrade debhelper-compat
sed -i -e 's/debhelper-compat (= 13)/debhelper-compat (= 12)/g' debian/control

# install build dependency
sudo apt-get build-dep libfdk-aac-dev

# build deb
dpkg-buildpackage -b -us -uc

# install deb
cd ..
sudo apt-get install ./*libfdk-aac-dev*.deb

Compile and install latest bluez-alsa¶

# clone and checkout
# as of this writing, HEAD is f0f9427da7d747cfe48b5c83b3076841f48d8703
git clone https://github.com/arkq/bluez-alsa
cd bluez-alsa

# install build dependency
sudo apt-get install automake build-essential libtool pkg-config python3-docutils
sudo apt-get install libasound2-dev libbluetooth-dev libdbus-1-dev libglib2.0-dev libsbc-dev libspandsp-dev

# build and install
autoreconf --install --force
mkdir build
cd build
../configure --enable-aac --enable-msbc --enable-systemd
make -j4
sudo make install

# update systemd service
sudo sed -i -e 's,^ExecStart=.*$,ExecStart=/usr/bin/bluealsad -S -p a2dp-source -p a2dp-sink -p hfp-ag -p hsp-ag,g' /lib/systemd/system/bluealsa.service
# disable pulseaudio, MUST BE RUN AS USER 'linaro'
systemctl --user disable --now pulseaudio pulseaudio.socket
sudo systemctl daemon-reload
sudo systemctl restart bluealsa

Check with Bluetooth handset¶

terminal-1: use bluetoothctl to connect with Bluetooth handset

bluetoothctl
Agent registered
[bluetooth]# scan on
# ^- turn on scan, lots of result follow
...
[bluetooth]# scan off
# find the handset mac shown above
# and do the pairing (replace the MAC with actual device MAC)
[bluetooth]# pair MAC
[bluetooth]# trust MAC
[bluetooth]# connect MAC

# show the device info, for example:
[DEV]# info
info
Device 38:F5:FA:A2:70:A0 (public)
        Name: W25
        Alias: W25
        Class: 0x00240404
        Icon: audio-card
        Paired: yes
        Trusted: yes
        Blocked: no
        Connected: yes
        LegacyPairing: no
        UUID: Audio Sink                (0000110b-0000-1000-8000-00805f9b34fb)
        UUID: A/V Remote Control Target (0000110c-0000-1000-8000-00805f9b34fb)
        UUID: A/V Remote Control        (0000110e-0000-1000-8000-00805f9b34fb)
        UUID: Handsfree                 (0000111e-0000-1000-8000-00805f9b34fb)
        UUID: PnP Information           (00001200-0000-1000-8000-00805f9b34fb)
        Modalias: bluetooth:v05D6p000Ad0240
        ManufacturerData Key: 0x7262
        ManufacturerData Value:
  32 32 78 78 11 22 33 44 55 66 aa bb 00 00        22xx."3DUf....

terminal-2: playback / record with the bluetooth device

# List the available BT audio PCMs:
$ sudo bluealsa-aplay -L
bluealsa:DEV=38:F5:FA:A2:70:A0,PROFILE=sco,SRV=org.bluealsa
    W25, trusted audio-card, capture
    SCO (mSBC): S16_LE 1 channel 16000 Hz
bluealsa:DEV=38:F5:FA:A2:70:A0,PROFILE=sco,SRV=org.bluealsa
    W25, trusted audio-card, playback
    SCO (mSBC): S16_LE 1 channel 16000 Hz
bluealsa:DEV=38:F5:FA:A2:70:A0,PROFILE=a2dp,SRV=org.bluealsa
    W25, trusted audio-card, playback
    A2DP (SBC): S16_LE 2 channels 48000 Hz

Playback:

sudo aplay -D bluealsa:DEV=38:F5:FA:A2:70:A0,PROFILE=a2dp,SRV=org.bluealsa /usr/share/sounds/alsa/Front_Center.wav

Record:

# -d 6: record 6 seconds
sudo arecord -f S16_LE -r 16000 -D bluealsa:DEV=38:F5:FA:A2:70:A0,PROFILE=sco,SRV=org.bluealsa -d 6 /tmp/a.wav

Control Volume:

$ sudo bluealsactl list-pcms
/org/bluealsa/hci0/dev_38_F5_FA_A2_70_A0/a2dpsrc/sink
/org/bluealsa/hci0/dev_38_F5_FA_A2_70_A0/hfpag/sink
/org/bluealsa/hci0/dev_38_F5_FA_A2_70_A0/hfpag/source

# Get Volume
$ sudo bluealsactl volume /org/bluealsa/hci0/dev_38_F5_FA_A2_70_A0/a2dpsrc/sink
Volume: 127 127

# Set Volume
$ sudo bluealsactl volume /org/bluealsa/hci0/dev_38_F5_FA_A2_70_A0/a2dpsrc/sink 100

Send and receive files¶

Bluetooth file sending and receiving can use the OBEX protocol, which encapsulates information data with an object model and transmits applications with a session protocol specification.

The Obex service is needed in Linux. Firstly, connect the EC-A1684JD4 to the Bluetooth device according to the previous steps, then start the Obex daemon, and set the receiving directory to /home/linaro/:

/usr/lib/bluetooth/obexd -r /home/linaro -a -d &

Use obex push service¶

First configure Bluetooth as master device mode:

sudo hciconfig hci0 lm master

Find the channel for the Obex Push service on your mobile phone:

linaro@bm1684:~$ sdptool search --bdaddr A4:90:CE:DF:64:4F OPUSH
Searching for OPUSH on A4:90:CE:DF:64:4F ...
Service Name: OBEX Object Push
Service RecHandle: 0x1000d
Service Class ID List:
  "OBEX Object Push" (0x1105)
Protocol Descriptor List:
  "L2CAP" (0x0100)
  "RFCOMM" (0x0003)
    Channel: 12
  "OBEX" (0x0008)
Profile Descriptor List:
  "OBEX Object Push" (0x1105)
    Version: 0x0102

Searching for OPUSH on A4:90:CE:DF:64:4F ...
Service Search failed: Invalid argument

You can see that the channel is 12, and then you can push the file to the phone:

linaro@bm1684:~$ obexftp --nopath --noconn --uuid none --bluetooth A4:90:CE:DF:64:4F --channel 12 --put sn.txt
Suppressing FBS.
Connecting..\done
Sending "sn.txt".../done
Disconnecting..-done

At this time, you can see the pop-up window whether to receive the file on the mobile phone.

Use obexctl interactive command line¶

The following demonstrates the steps for EC-A1684JD4 to receive files:

(1) Start the obex service on the device side (slave device):

root@firefly:~# systemctl --user start obex

(2) Enter the interactive command line:

root@firefly:~# obexctl 
[NEW] Client /org/bluez/obex 

(3) Connect EC-A1684JD4 (master device):

[obex]# connect 20:57:9E:BA:7C:EC
Attempting to connect to 20:57:9E:BA:7C:EC
...
[NEW] Session /org/bluez/obex/client/session2 [default]
[NEW] ObjectPush /org/bluez/obex/client/session2 

(4) Send files:

[20:57:9E:BA:7C:EC]# send /root/test.txt
Attempting to send /root/test.txt to /org/bluez/obex/client/session1
[NEW] Transfer /org/bluez/obex/client/session1/transfer1
Transfer /org/bluez/obex/client/session1/transfer1
        Status: queued
        Name: test.txt
        Size: 0
        Filename: /root/test.txt
        Session: /org/bluez/obex/client/session1
[CHG] Transfer /org/bluez/obex/client/session1/transfer1 Status: complete

(5) Check the test.txt file in the /home/linaro/ directory of EC-A1684JD4:

linaro@bm1684:~$ ls -l test.txt
-rw------- 1 linaro linaro 0 Nov 25 15:49 test.txt