OpenCarPro

dt is a devicetree, a descriptor of which hardware is present and enabled on a SOC. uboot uses devictrees for board specifics. the linux kernel hosts devicetrees in it's source code, but it can be used by any other OS.

https://raspberry-projects.com/pi/pi-operating-systems/raspbian/bluetooth/bluetooth-commands

/boot/config.txt
#dtoverlay=bt-disable
dtparam=audio=on

usb bluetooth

https://bluewavestudio.io/community/showthread.php?tid=2915 https://bluewavestudio.io/community/showthread.php?tid=2009 https://github.com/raspberrypi/linux/issues/3269

systemctl status hciuart.service
/proc/device-tree/soc/gpio@7e200000/bt_pins/brcm

rfkill
rfkill list all

systemctl start hciuart
sudo systemctl start hciuart.service

hcitool dev
hcitool scan
hciconfig features

apt install raspberrypi-sys-mods

CSR 4.0 compatible

bluetoothctl version

bluetoothctl
[Bluetooth]# del 38:78:62:A6:29:BD
[Bluetooth]# connect 38:78:62:A6:29:BD
[Bluetooth]# info 38:78:62:A6:29:BD 

[Bluetooth]# list
[Bluetooth]# devices
[Bluetooth]# power on
[Bluetooth]# scan on
[Bluetooth]# pair
[Bluetooth]# trust

lspci -v
modprobe btusb
usermod -G bluetooth -a pi

hcitool dev

broadcom-sta-dkms

https://github.com/winterheart/broadcom-bt-firmware/tree/master/brcm

sudo cp BCM43142A0* /lib/firmware/brcm/BCM.hcd

-compat
sdptool

Wireless hotspot
openauto_system.ini file:

[Wireless]
HotspotEnabled=false
Enabled=true
Ssid=OpenAutoPro
Bssid=
Key=1234567890
Port=5000
HotspotBand=1

sudo bwshotspot enable OpenAutoPro 1234567890 a
"g" => 2.4Ghz and "a" => 5Ghz 

https://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Modules/

arecord -l

/home/pi/.asoundrc
pcm.mic {
  type plug
  slave {
    pcm "hw:[card number],[device number]"
  }
}
alsamixer