原标题：基于Microchip IS2064GM-OL3搭载Sony LDAC技术的蓝牙高清耳机方案

　　随着主流消费者对优质音讯体验的需求不断增强，消费者希望蓝牙音讯设备提供完美的无间断音讯体验。然而，蓝牙音讯设计通常受限于现有编解码器(用于通过无线电波发送音讯的通信和压缩技术)的位深和频率， 传统的蓝牙音频传输技术，在传输LPCM音讯前，会先解析到44.1kHz/16 bit，然后经过328kbps的传输。这对之后产生的音质折损率非常大. 主要的CODEC参数参见下图

　　编译码性能对比

　　LDAC是SONY独家研发的一种音频编码技术， 简单来讲LDAC就是一种能够无线传输高分辨率音频的编码技术，采用无线的手段就可以传输码率990kbps的音讯。这也足以媲美CD级别的音质了。

　　LDAC技术的诞生虽然让蓝牙无线音质也能够达到Hi-Res级别，但这项技术起初却被索尼自己独占，用户必须在索尼自家的智慧手机、播放器、耳机、音响等产品上才能使用。所以，LDAC也成为了索粉的“专属福利”。

　　而如今， Sony 为了LDAC的全球普及， 向Andrion 8.0提供了 LDAC技术 ,以后只要是安装了Android O的手机，就都能够利用LDAC，在支持该技术的播放系统上让用户享受无线的高清音乐了。

　　Microchip 对LDAC技术有着非常广博认识和丰富的开发经验。与Sony 在LDAC上合作超过5年，为Sony定制了多种LDAC的蓝牙平台， 并成功批量生产。本方案采用BM64GM-0L3为蓝牙平台，它是IC IS2064GM-0L3对应的模块.

　　本方案以8bit MCU PIC18F85J10 为主控，通与UART接口 实现与BM64GM的命令与事件的交互;DSP CODEC采用YAMAHA YDA174A30,MCU 通过I2C及3个IO配置和控制 CODEC。本方案是一个完整的Bluetooth®Multi-Speaker and LDAC Audio Application 的交钥匙方案.可应用于高端高质量的无线音响，Sound-Bar,耳机，Portable Speaker. MCU软件同时支持PIC16F15345,其简化了BLE，codec功能，应用于耳机市场性价比更高。 详细软件代码参考数据可在数据中下载，用户可根据具体应用来裁剪。

　　其驱动软件架构见下图：

　　方案可支持24bit/96Khz audio on I2S Digital aduio实测I2S资料如下

　　方案可支持BT SBC ,LDAC码流， AIR-LOG 的抓到LDAC(normal)的码流：

　　场景应用图

　　展示板照片

　　方案方块图

　　核心技术优势

　　1.蓝牙LDAC高清音乐

　　2.无线组网(Muti-Speaker 应用)--连接多达100个蓝牙无线音箱，且音乐和数据同步

　　3.支持BLE数据传输

　　4.支持LINEIN

　　5.蓝牙通话

　　方案规格

　　1.高保无线音乐，支持SBC ,AAC,LDAC， 码流330~990Kbps

　　2.自动无线组网功能

　　3. HD Voice (Wideband Audio)

　　4. 24-bit/96kHz Audio on I2S Digital Audio

　　5. 98dB SNR DAC Playback

　　6. 92dB SNR ADC for MIC-in

　　7. 1mA@Stanby,0.04mA@Power 0ff

　　8.Temperature and Voltage Sensing

　　技术文档

    【PIC18F85J10】

　　Features:

　　40 MHz and 12 MIPS at 3V

　　Flash 10,000 endurance, 20 years retention

　　2.0 - 3.6V voltage range

　　5V tolerant digital inputs

　　Enhanced ICD with 3 HW breakpoints

　　Device Overview

　　Summary

　　Ideal for cost sensitive applications that benefit from the availability of four serial ports: two synchronous serial ports (I²C™ and SPI™) and two asynchronous (LIN capable) serial ports. Large amounts of Flash program memory and RAM make it ideal for instrumentation panels, TCP/IP enabled embedded applications as well as metering, industrial control and monitoring applications. While operating up to 40 MHz at 3V, this family of general purpose devices targets cost sensitive designs with 1k Flash endurance, emulated EEPROM, and external crystal or clock source.

　　Additional Features

　　40 MHz and 12 MIPS at 3V

　　Flash 10,000 endurance, 20 years retention

　　2.0 - 3.6V voltage range

　　5V tolerant digital inputs

　　Enhanced ICD with 3 HW breakpoints

　　Parametrics

　　Name：Value

　　Program Memory Type：Flash

　　Program Memory Size (KB)：32

　　CPU Speed (MIPS/DMIPS)：10

　　SRAM Bytes：2,048

　　Digital Communication Peripherals：2-UART, 2-SPI, 2-I2C2-MSSP(SPI/I2C)

　　Capture/Compare/PWM Peripherals：5 Input Capture, 2 CCP, 3 ECCP,

　　Timers：2 x 8-bit, 3 x 16-bit

　　ADC Input：15 ch, 10-bit

　　Number of Comparators：2

　　Temperature Range (C)：-40 to 85

　　Operating Voltage Range (V)：2 to 3.6

　　Pin Count：80

     【IS2064】

　　Features:

　　Codec support for SBC, AAC, and LDAC (IS2064GM-0L3 only)

　　Bluetooth 5 Certified

　　Portable Speakers

　　Multiple Speaker Support

　　Device Overview

　　Summary

　　The IS2064 products are part of our Bluetooth Dual Mode family of stereo audio SoCs. Three variants are offered in a variety of packages, form factors and memory configurations. The IS2064GM is a Flash-based device that can be programmed to support a variety of speaker configurations. The IS2064S/B are ROM-based devices featuring Stereo Mode functionality, which allows audio playback on two devices.

　　All variants support SBC and AAC Codecs. The IS2064GM-0L3 supports LDAC. For more information contact your local Microchip representative or send an email to BTAudio@microchip.com.

　　Additional Features

　　Bluetooth Features

　　Codec support for SBC, AAC, and LDAC (IS2064GM-0L3 only)

　　Bluetooth 5 Certified

　　Support to simultaneously connect to two audio sources via HFP and/or A2DP

　　Generic Access Service

　　Device Information Service

　　Proprietary Services for data communication

　　HFP 1.6

　　HSP 1.2

　　A2DP 1.3

　　SPP 1.2

　　AVRCP 1.6

　　System Features

　　Built-in internal Flash for program memory (IS2064GM)

　　16 MHz main clock input

　　USB firmware upgrade supported

　　Three LED drivers

　　Built-in EEPROM

　　Integrated 3V, 1.8V configurable switching regulator and LDO

　　Crystal oscillator with built-in digital trimming for temperature/process variations

　　Built-in ADC for battery monitor and voltage sense

　　Built-in Lithium-ion battery charger (up to 350mA)

　　RF Features

　　Adaptive Frequency Hopping (AFH) avoids occupied RF channels

　　Fully supports Bluetooth BDR/EDR/BLE specification

　　Combined TX/RX RF terminal simplifies external matching and reduces external antenna switches

　　Maximum +4 dBm output power

　　Built-in T/R switch for Class 2/3 application

　　There requires no external VCO, varactor diode, resonator and loop filter

　　Supports 64 kb/s A-Law or µ-Law PCM format, or CVSD (Continuous Variable Slope Delta Modulation) for SCO channel operation.

　　Audio Features

　　Fully integrated synthesizer

　　Noise suppression

　　Echo suppression

　　SBC and optional AAC decoding

　　Packet loss concealment

　　Supports SCMS-T

　　20 bit DAC and 16 bit ADC codec

　　98dB SNR DAC playback

　　Supports digital audio I2S format and analog audio output

　　A line-in port for external audio input

　　High speed HCI-UART (Universal Asynchronous Receiver Transmitter) interface(up to 921600bps)

　　Applications

　　Headsets

　　Headphones

　　Portable Speakers

　　Multiple Speaker Support

　　Parametrics

　　Name：Value

　　Bluetooth Classic-Data/SPP：Yes

　　Bluetooth Classic-Audio：Yes

　　Bluetooth Low Energy：Yes

　　Audio Channels：Stereo

　　Analog Audio Out：Yes

　　Digital Audio Out：Yes

　　MIC-in：1

　　Line-in：Yes

　　GPIO：15

　　Package Type：68-pin LGA, 68-pin QFN, 61-pin BGA

　　Package Size：8x8 LGA, 8x8 QFN, 5x5 BGA

　　Temperature Range：-20 C to +70 C

　　Operating Voltage Range：3.2 V to 4.2 V