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ipro_le_audio_headset

LE Audio ユニキャストヘッドセット：BAP unicast server、PACS、ASCS、CAP、CSIP、VCP。LC3 をデコードして DAC に出力します。チュートリアル：LE Audio 入門

項目 内容
ソースコード apps/bluetooth/le_audio/ipro_le_audio_headset
ボードと設定 Reef（defconfig_reef：DAC 出力をヘッドセットジャックとスピーカーへ）、.config、DAC.config、UAC.config は IPRO7 EVB 用
コンソール UART 115200
ビルド Reef：make -C apps/bluetooth/le_audio/ipro_le_audio_headset DEFCONFIG=defconfig_reef

Reef で動かす

  1. ビルド

    make -C apps/bluetooth/le_audio/ipro_le_audio_headset DEFCONFIG=defconfig_reef

    イメージは apps/bluetooth/le_audio/ipro_le_audio_headset/build_reef/build_out/ipro_le_audio_headset_IPRO7.bin です。

  2. 書き込み：ダウンロードモードに入り、IntelProCube のディレクトリで次を実行します。

    ./ipro_iot_tool_macos --chipname ipro7 --chip-variant IPRO7AI \
    --port /dev/cu.usbserial-XXXX --baudrate 921600 \
    --firmware <SDK>/apps/bluetooth/le_audio/ipro_le_audio_headset/build_reef/build_out/ipro_le_audio_headset_IPRO7.bin

    [All Success] を確認してから SW2 を押します。

  3. 実行：115200 baud でコンソールを開きます。ボードは IPRO-LE-Audio としてアドバタイズします。LE Audio 対応のスマートフォンからペアリングします（数値比較はボード側で自動的に承認されます）。コンソールで leaudio_status と入力すると、接続とストリームの状態が表示されます。SW3、SW4、SW5 は VCP による音量ダウン、音量アップ、ミュートです。

本リリースでの状態

アプリケーションの README には、スマートフォンからの接続、サービス探索、セキュリティレベル 4 でのボンディングまで動作すると記載されています。スマートフォンからのメディアストリーミングはまだ検証されていません。

README

README の原文

以下はアプリケーションに付属する README（SDK V2.2.1）を原文のまま掲載したものです。翻訳はしておらず、公開に適さない内容だけを置き換えています。

Overview

LE Audio Unicast Headset bring-up application for the new IPRO BLE controller component and unified Zephyr-derived host.

Current validated status is profile/HCI ISO payload bring-up, not a finished customer audio product:

  • peripheral advertising as IPRO-LE-Audio
  • SMP/settings/bonding enabled
  • BAP unicast server, PACS, ASCS, CAS and VCP Volume Renderer enabled
  • CIS setup and ISO RX payload path validated with the two-board central test
  • UART shell enabled at 115200
  • controller config: link1_periph, feature profile bt54_iso2, EM 32 KiB
  • audio output/render is currently disabled; LC3 decode/render and acoustic validation remain open

The two-board automated peer used for this validation (ipro_ble_controller_central_test) is an internal test app and is not part of the SDK package; any LE Audio unicast client can act as the peer.

Android phone basic status:

  • Pixel 10 Pro / Android 17 can scan/connect to IPRO-LE-Audio.
  • Android GATT service discovery has found 1801,1853,1850,184e,1844.
  • Android system Bluetooth reports LE Audio connected and Volume Control connected.
  • Actual LE Audio media streaming is not yet validated; Android currently reports zero connected audio channels with this firmware.

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                    PC/Smartphone (LE Audio Source)              │
│                                                                   │
│  ┌──────────────┐   ┌──────────────┐   ┌──────────────┐        │
│  │  Music App   │   │ Volume Ctrl  │   │ Media Ctrl   │        │
│  └──────┬───────┘   └──────┬───────┘   └──────┬───────┘        │
│         │                  │                   │                 │
│         ▼                  ▼                   ▼                 │
│  ┌────────────────────────────────────────────────────┐         │
│  │         BLE LE Audio Unicast Client (CAP)          │         │
│  │  ┌──────────┐  ┌──────────┐  ┌──────────┐         │         │
│  │  │   BAP    │  │   VCP    │  │   MCP    │         │         │
│  │  └──────────┘  └──────────┘  └──────────┘         │         │
│  └────────────────────────────────────────────────────┘         │
└───────────────────────────────┬─────────────────────────────────┘
                                │ BLE Link (CIS)
                                │ LC3 Encoded Audio
                                ▼
┌─────────────────────────────────────────────────────────────────┐
│              IPRO7 LE Audio Unicast Headset                     │
│                                                                   │
│  ┌────────────────────────────────────────────────────────┐     │
│  │              BLE LE Audio Server Stack                 │     │
│  │  ┌──────────┐  ┌──────────┐  ┌──────────┐  ┌──────┐  │     │
│  │  │ BAP      │  │ VCP      │  │ MCP      │  │ CCP  │  │     │
│  │  │ Unicast  │  │ Server   │  │ Server   │  │      │  │     │
│  │  │ Server   │  │          │  │          │  │      │  │     │
│  │  └────┬─────┘  └────┬─────┘  └────┬─────┘  └──────┘  │     │
│  └───────┼─────────────┼─────────────┼───────────────────┘     │
│          │             │             │                           │
│  ┌───────▼─────────────▼─────────────▼───────────────────┐     │
│  │         GAF (Generic Audio Framework)                  │     │
│  └────────────────────────┬───────────────────────────────┘     │
│                           │                                      │
│  ┌────────────────────────▼───────────────────────────────┐     │
│  │              Audio Data Path                           │     │
│  │  ┌──────────┐  ┌──────────┐  ┌──────────┐             │     │
│  │  │ ISOOHCI  │→ │   LC3    │→ │   Ring   │             │     │
│  │  │ Receive  │  │ Decoder  │  │  Buffer  │             │     │
│  │  └──────────┘  └──────────┘  └────┬─────┘             │     │
│  │                                    │                    │     │
│  │  ┌──────────┐  ┌──────────┐  ┌────▼─────┐             │     │
│  │  │ ISOOHCI  │← │   LC3    │← │   Ring   │             │     │
│  │  │ Transmit │  │ Encoder  │  │  Buffer  │             │     │
│  │  └──────────┘  └──────────┘  └──────────┘             │     │
│  └────────────────────────┬───────────────────────────────┘     │
│                           │                                      │
│  ┌────────────────────────▼───────────────────────────────┐     │
│  │              USB Audio Class (UAC)                     │     │
│  │  ┌──────────────────┐      ┌──────────────────┐       │     │
│  │  │  UAC Playback    │      │  UAC Capture     │       │     │
│  │  │  (Speaker Out)   │      │  (Mic In)        │       │     │
│  │  └────────┬─────────┘      └────────▲─────────┘       │     │
│  └───────────┼──────────────────────────┼─────────────────┘     │
└──────────────┼──────────────────────────┼───────────────────────┘
               │                          │
               ▼                          │
        ┌─────────────┐          ┌───────┴──────┐
        │   Speaker   │          │  Microphone  │
        └─────────────┘          └──────────────┘

Key Features

Audio Profiles

  • BAP (Basic Audio Profile): Unicast audio streaming with CIS (Connected Isochronous Stream)
  • VCP (Volume Control Profile): Remote volume control from source device
  • MCP (media control) and CCP (call control) are not enabled in the shipped .config (no CONFIG_BT_MCC / CONFIG_BT_MCS)

Audio Capabilities

  • Codec: LC3 (Low Complexity Communications Codec)
  • Sample Rates: 16kHz, 24kHz, 32kHz, 48kHz
  • Frame Duration: 7.5ms, 10ms
  • Bitrates: 32kbps - 96kbps (configurable)
  • Bidirectional Audio: Simultaneous playback and capture

Advanced Features

  • Auto-reconnection: Automatically reconnect to paired devices
  • Battery Service: Report battery level to connected device
  • Device Information Service: Expose device info (model, firmware version)
  • GATT Caching: Faster reconnection with cached GATT database
  • Smart Power Management: Optimized for low power consumption

Shell Commands

# Volume Control
volume get                    # Get current volume
volume set <0-255>           # Set volume level
volume mute                  # Mute audio
volume unmute                # Unmute audio

# Media Control
media play                   # Start playback
media pause                  # Pause playback
media next                   # Next track
media prev                   # Previous track

# Connection Management
gap disconnect               # Disconnect from source
gap advertise <on|off>       # Control advertising

# Audio Control
audio status                 # Show audio stream status

DEMO Application Scenarios

Scenario 1: Wireless Music Listening

Use Case: Listen to music from smartphone/PC wirelessly

Setup:

  1. Power on IPRO7 headset → auto-start advertising
  2. On smartphone: Open Bluetooth settings → Connect "IPRO-Headset"
  3. Open music app → Select IPRO-Headset as audio output
  4. Play music → Audio streams via BLE LE Audio

User Experience:

  • High-quality audio with LC3 codec (better than SBC)
  • Low latency (~20-40ms)
  • Phone volume controls work seamlessly
  • Media play/pause buttons control smartphone playback

Scenario 2: Video Conference with Bidirectional Audio

Use Case: Join video conference call with microphone support

Setup:

  1. Connect IPRO7 headset to PC
  2. Join Zoom/Teams meeting
  3. Select "IPRO-Headset" for both speaker and microphone
  4. Bidirectional audio automatically established

User Experience:

  • Clear voice transmission with LC3 encoding
  • Echo cancellation enabled
  • Low latency for natural conversation
  • USB audio seamlessly bridges BLE and PC

Scenario 3: Gaming with Low-Latency Audio

Use Case: Play mobile games with minimal audio delay

Setup:

  1. Connect to gaming smartphone
  2. Launch game application
  3. Audio automatically routes to headset with optimized latency

User Experience:

  • Fast audio response (<30ms typical)
  • Synchronized audio and visual feedback
  • Volume adjustable without leaving game

Scenario 4: Smart Home Voice Assistant

Use Case: Interact with voice assistant (Siri/Google Assistant)

Setup:

  1. Connected to smartphone
  2. Trigger voice assistant with button or wake word
  3. Audio I/O handled by headset

User Experience:

  • Clear voice command capture
  • Assistant responses play through headset
  • Hands-free operation

Build Instructions

Prerequisites

  • IPRO SDK properly set up
  • RISC-V toolchain installed (/opt/toolchain/riscv_ipro7/)

Build Command

cd <SDK root>
PATH=/opt/toolchain/riscv_ipro7/bin:$PATH \
IPRO_SDK_BASE=$(pwd) \
make -C apps/bluetooth/le_audio/ipro_le_audio_headset -j8

Build Output

  • Binary: apps/bluetooth/le_audio/ipro_le_audio_headset/build/build_out/ipro_le_audio_headset_IPRO7.bin
  • Latest recorded basic build: 521080 B, SHA256 55074c89ae853bb462af90f3cdd0129a4ccad42cd8163d9774ac2ad20be6473f.

Flash to Device

# $CUBE_UTILS is the utils/ directory of your IntelProCube installation.
# The port name changes with the USB adapter - check `ls /dev/cu.*` rather
# than assuming, and use cu.* not tty.* (the latter blocks on carrier detect).
python3 "$CUBE_UTILS/ipro_probe_ctl.py" \
  dl --port /dev/cu.usbmodemXXXX

"$CUBE_UTILS/ipro_flash.sh" \
  --chipname ipro7 \
  --port /dev/cu.usbmodemXXXX \
  --firmware apps/bluetooth/le_audio/ipro_le_audio_headset/build/build_out/ipro_le_audio_headset_IPRO7.bin

IPRO7AI Reef board

make -C apps/bluetooth/le_audio/ipro_le_audio_headset DEFCONFIG=defconfig_reef
# -> build_reef/build_out/ipro_le_audio_headset_IPRO7.bin
ipro_iot_tool_macos --chipname ipro7 --chip-variant IPRO7AI --port /dev/cu.usbmodemXXXX \
    --firmware apps/bluetooth/le_audio/ipro_le_audio_headset/build_reef/build_out/ipro_le_audio_headset_IPRO7.bin

defconfig_reef is the DAC variant with CONFIG_IPRO7AI_REEF instead of CONFIG_EVB, and CCI analysis off (it claims GPIO0/1/2/11: camera D0-D2 and SW5 on this board). Board behaviour comes from ipro7ai_reef_board_config.h:

  • Output: DAC A feeds both the J2 headphone buffer and the PAM8302A speaker amp (enable GPIO25). While a plug is in J2 (GPIO26 low) the amp is off; it follows the jack during playback. The speaker path is trimmed by -12 dB (dac spk <dB>), because the PAM8302A's 15-30 V/V gain is far above the EVK amp the volume curve was set on. The EVK speaker EQ is off.
  • Keys: SW3 volume down, SW4 volume up, SW5 mute, all through the VCP volume renderer, so the phone's slider follows.
  • 512 kHz output path (dac os 1, the Reef default): the GPDAC runs at 512 kHz and src/dac_ns.c expands each 32 kHz sample with interpolation and first-order noise shaping, which takes the 10-bit quantisation hiss out of the audio band. dac os 0 is the original 32 kHz path, dac os 2 second-order shaping. The expander costs about 8% CPU (ps). It runs at priority 5, below the BLE host threads: at priority 30 the stream lost 4-13% of its ISO packets; at 5, none in 13 000 packets on either path (bench, 2026-10-06). ps and long dacprof/dac status dumps stall it for a moment and can cause a short glitch.

Host test for the shaper: sh test_host/run.sh.

Basic Android phone smoke

With the headset app running on A:

cd <SDK root>
PATH=/opt/toolchain/riscv_ipro7/bin:$PATH \
IPRO_SDK_BASE=$(pwd) \
python3 apps/bluetooth/le_audio/ipro_le_audio_headset/tools/verify_le_audio.py \
  --port /dev/cu.usbmodemXXXX \
  --baud 115200 \
  --duration 45 \
  --device IPRO-LE-Audio \
  --expect-ascs \
  --log /tmp/ipro_android_leaudio_smoke_board.log \
  --json /tmp/ipro_android_leaudio_smoke.json

Latest recorded r48 result:

  • Android found IPRO-LE-Audio, connected, and discovered 1801,1853,1850,184e,1844.
  • The phone bonded successfully; the DUT reported security level 4.
  • This verifies phone visibility/profile connection, not media streaming.

Configuration

Kconfig Options

Key configuration options in .config (DAC.config and UAC.config switch the audio output between the on-chip DAC and a USB Audio Class device):

# LE Audio roles (Zephyr host)
CONFIG_BT_AUDIO=y
CONFIG_BT_AUDIO_RX=y
CONFIG_BT_BAP_UNICAST_SERVER=y
CONFIG_BT_PACS=y
CONFIG_BT_ASCS=y
CONFIG_BT_CAP_ACCEPTOR=y
CONFIG_BT_CSIP_SET_MEMBER=y
CONFIG_BT_VCP_VOL_REND=y

# LC3 decoder
CONFIG_COMPONENTS_LC3_ENABLE=y

Audio Parameters

Configurable in src/app_audio.h:

#define APP_AUDIO_SAMPLE_RATE      48000   // Hz
#define APP_AUDIO_FRAME_DURATION   10      // ms
#define APP_AUDIO_BITRATE          96      // kbps
#define APP_AUDIO_CHANNELS         2       // Stereo

Development Roadmap

Phase 1: Core Features ✅ (Completed)

  • [x] Basic BAP unicast audio streaming
  • [x] LC3 codec integration
  • [x] USB audio bridge
  • [x] VCP volume control
  • [x] Auto-reconnection support

Phase 2: Enhanced User Experience (Q1 2026)

  • [ ] Multipoint Connection: Connect to 2 devices simultaneously
  • [ ] Fast Pair Support: Google Fast Pair for quick pairing
  • [ ] AVRCP Fallback: Support classic Bluetooth for older devices
  • [ ] Battery Optimization: Extend battery life by 30%
  • [ ] Custom EQ: User-configurable audio equalization

Phase 3: Advanced Audio Features (Q2 2026)

  • [ ] Broadcast Audio Scan: Scan and join Auracast broadcasts
  • [ ] Audio Sharing: Share audio with another headset
  • [ ] Spatial Audio: 3D audio positioning support
  • [ ] Hearing Aid Features: Customizable audio amplification
  • [ ] Active Noise Cancellation: ANC integration

Phase 4: Ecosystem Integration (Q3 2026)

  • [ ] CCP Full Implementation: Complete call control profile
  • [ ] HAP Integration: Hearing Access Profile for accessibility
  • [ ] TMAP Support: Telephony and Media Audio Profile
  • [ ] Multi-language Voice Prompts: Localized user feedback
  • [ ] OTA Firmware Update: Over-the-air update via BLE

Phase 5: AI and Smart Features (Q4 2026)

  • [ ] AI Noise Reduction: Deep learning-based noise cancellation
  • [ ] Voice Enhancement: AI-powered voice clarity
  • [ ] Context Awareness: Automatic audio mode switching
  • [ ] Personalized Audio: Learning user preferences
  • [ ] Health Monitoring: Heart rate/activity tracking integration

Technical Specifications

Performance Metrics

  • Audio Latency: 20-40ms (typical)
  • Connection Range: Up to 10 meters (Class 2)
  • Battery Life: 8+ hours continuous playback
  • Standby Time: 200+ hours
  • Charging Time: ~2 hours

Memory Usage

  • Flash: ~550 KB
  • RAM: ~140 KB (OCRAM)
  • PSRAM: ~2 MB (audio buffers)

Supported Platforms

  • IPRO7 Development Board
  • IPRO7 Commercial Modules
  • Future: IPRO8 platform

Troubleshooting

Common Issues

Issue: Headset not discoverable

  • Solution: Check if advertising is enabled: gap advertise on

Issue: No audio output

  • Solution: Verify USB connection and check audio status command

Issue: Poor audio quality

  • Solution: Check RSSI (gap status) and ensure strong BLE signal

Issue: Volume control not working

  • Solution: Ensure VCP is enabled in configuration and source device supports it

Issue: Disconnection during audio playback

  • Solution: Check for interference, reduce distance, or update firmware

References

License

Copyright (c) 2024-2026 INTELPRO Inc. All rights reserved.

Contact

For technical support or questions:

  • Email: support@intelpro.com.tw
  • Website: https://www.intelpro.com.tw