Raspberry Pico W or Pico2 W A2DP Sink to I2S/DAC

Use a Raspberry Pico W or Pico2 W to receive music from a smartphone or other bluetooth A2DB source and send it via I2S to a DAC like the PCM5102.

Based on the BTStack a2db-sink demo of the pico-examples repo. Not being embedded in the build structure of all examples makes it much easier to see what is actually required, to modularize and enhance. Still uses pico-extras for i2s audio.

Feel free to ask if you need help to get this running. Comments or improvements welcome :)

Programming

• Clone Pico-SDK, Pico-Extras and PicoW_A2DP from Github, build and flash
• tested >= 1.5.0 for Pico W, >= 2.1.0 for Pico2 W

base=~/pico-2.1.0
mkdir "$base"
cd "$base"
git clone git@github.com:raspberrypi/pico-sdk.git --branch 2.1.0
cd pico-sdk
git submodule update --init
cd ..
export PICO_SDK_PATH="$base"/pico-sdk
git clone git@github.com:raspberrypi/pico-extras.git --branch sdk-2.1.0
export PICO_EXTRAS_PATH="$base"/pico-extras/
git clone https://github.com/joba-1/PicoW_A2DP.git
cd PicoW_A2DP/
mkdir build && cd build

# cmake -DPICO_BOARD=pico_w -DCMAKE_BUILD_TYPE=Debug ..
cmake -DPICO_BOARD=pico2_w -DCMAKE_BUILD_TYPE=Debug ..

make -j
# boot pico into flash mode before this: 
cp picow-a2dp.uf2 /run/media/$USER/RP2??0/

• For optional flashing/debugging with a picoprobe connect Pico-W power-, debug- and optionally uart-pins and clone OpenOCD Pico Branch from raspberrypi github

Configuration

• Used pins for connectiong the DAC are defined in CMakeLists.txt
• Bluetooth name and pin also defined in CMakeLists.txt
• If RUN_PIN is defined the pin will be used to pull down RUN pin to reset on fatal errors
• CONN_PIN high indicates active bt connection (I use it to switch my AV receiver input)

Debugging / Flashing

Use commandline to cmake the firmware, then copy the UF2 to the USB filesystem or use picoprobe and openocd to flash the firmware and openocd/gdb to debug. Alternatively use VS Code with CMake Tools and Cortex Debug extensions as a build/debug environment. To help VS Code find your openocd binary, add it in ~/.config/Code/User/settings.json before the closing "}" similar to this:

    "cortex-debug.openocdPath": "/home/joachim/pico/openocd/src/openocd"

To flash/debug with VS Code, select "Run and Debug" or Ctrl+Shift+D, at the top select "Pico Debug (your project)". Now the green arrow or F5 flashes the new firmware and starts a debug session.

WIP

Currently done:

• separate the demo from the pico-examples repo.
• enable debugging with picoprobe and VS Code
• modularize bt functionality: i2s, avrcp, a2dp, sdp and generic bt Target is to have a modular design with stable functionality for everyday use.

Status is: works pretty well with Pico W and Pico2 W

Added Features

• LED functions
  • on during boot
  • show a2dp connection status
  • blink on fatal errors
• configurable BT device name and BT connection pin
• configurable hard reset via pin
• Volume control
• Reboot on disconnect to work around buggy reconnect
• Support pico2_w (just change the board type for cmake)