WT2605B03 MP3 Audio Bluetooth Voice Module

Product Overview

The WT2605B03-V2.02 audio Bluetooth module is an intelligent wireless audio data transmission and MP3 audio playback product developed independently by Waytronic Electronics of Guangzhou. It offers a cost-effective and efficient stereo wireless transmission solution, featuring high integration, small size, low power consumption, and fast transmission speed. By adding only a few peripheral components, high-quality stereo audio can be wirelessly received. The module operates without drivers; customers need only connect the chip to their application products to quickly achieve wireless music transmission and enjoy the benefits of Bluetooth chips. The WT2605B03-V2.02 primarily has three functional features: built-in MP3 functionality, dual-mode Bluetooth capability, and UART serial port control. The module includes internal Flash memory and supports external USB drives and TF cards.

Product application fields

This module is primarily used for short-distance music transmission and can easily connect with Bluetooth devices of digital products such as laptops, mobile phones, and tablets, enabling wireless music transfer.
• Bluetooth speakers
• Bluetooth stereo headphones
• Hands-free phone calls
• Car audio systems
• Car hands-free
• Portable navigation devices

Module features

• Operating voltage range of the chip: 3.3V-5.0V;
• WT2605 is a dual-mode Bluetooth module, supporting both audio Bluetooth and data transmission Bluetooth, conforming to Bluetooth 5.0 and BLE standards;
• After powering on, the Bluetooth module searches for audio Bluetooth named ‘BT_WT2605’ and BLE Bluetooth named ‘LE_WT2605’;
• Bluetooth crystal parameters: 26MHz _11pF, ±10PPM, must select the crystal according to these parameters;

• After connecting to a phone via Bluetooth, it displays the Bluetooth battery icon, showing 100% at >=4.2V, 20% at 3.3V, with an average of 8%-10% per 0.1V. To disable the battery display, please communicate in advance with our sales team;
• The Bluetooth connection distance should ideally be within 10 meters for better performance. Refer to Chapter 8 below for Bluetooth chip layout;
• Utilizes WT2605 as the core, supporting SPI-FLASH, TF card, and USB drive storage methods. SPI-FLASH stores fixed audio sources, which can be replaced using a USB drive. It supports up to 128Mbit Flash, 32GB TF card, and 32GB USB drive;
• Our Bluetooth audio function mainly includes two modes: Bluetooth mode and MP3 mode. Upon power-on, it defaults to Bluetooth mode, allowing connection through phone Bluetooth. In MP3 mode, control the playback of audio from Flash, TF card, or USB drive via serial port commands. Both modes cannot run simultaneously;
• Standard UART communication interface, enabling flexible functions such as playing specified address files, specified file names, files within specified folders, volume levels, next/previous tracks, play/pause, storage switching, and selecting playback modes;
• USB interface functions: 1) Supports USB drive playback; 2) When the chip is connected to a TF card, connecting USB to PC shows the TF card drive letter, similar to a card reader, allowing file copying; 3) Provides USB drive firmware upgrade function; 4) When connected to a computer, it has sound card functionality. When used as a sound card, Bluetooth playback cannot be used due to occupied audio channels. Disconnect USB for Bluetooth audio output;
• Supports FAT, FAT16, FAT32 file systems, and MP3, WAV formats (PCM, IMA-ADPCM require micro-customization. General formats are MP3 and WAV with sampling rates 8K-44.1K, bit rate <=320kbps);
• In MP3 mode, when both USB drive and TF card are present, it responds to USB drive first, then TF card. Supports hot-plugging of USB drive/TF card;
• Typical TX output power: +2dB;
• Audio codec supports 16-bit stereo DAC and two-channel 16-bit ADC;
• High-performance stereo, ADC with 90dB signal-to-noise ratio;
• Three multifunctional 32-bit timers, supporting capture and PWM modes;
• Customizable functions: button control mode, infrared control mode, etc.;
• After power-on initialization, the chip automatically returns a code: 7E 04 01 00 05 EF. It is recommended to have a 200ms interval between command codes;
• Power-on default is Bluetooth mode. Open phone Bluetooth to search and connect. After connecting to Bluetooth, the chip’s TX pin returns: 7E 05 C2 0B 02 D4 EF. Disconnecting Bluetooth automatically returns: 7E 05 C2 08 02 D1 EF. For detailed C2 command instructions, refer to the relevant documentation;
• Standard Bluetooth module program does not include contact list functionality. Current common features are: Bluetooth + MP3 + BLE. Due to internal resource limitations, the contact list feature is made separately. If you need Bluetooth and contact list functionality, please contact our sales team for corresponding program firmware;
• Important note: If the voice chip requires an external flash memory, It is recommended to use the flash produced by ‘Waytronic’, as the compatibility of flash from other manufacturers cannot be guaranteed. (It is suggested to mark the compatibility expansion for 150mil and 208mil dimensions, which makes it more convenient for stock preparation); Support for USB drive firmware upgrades for the module, it is recommended to reserve a USB interface when designing the board.

Functional block diagram introduction

Internal structure of the module: audio Bluetooth chip, Flash memory, 26MHz crystal oscillator, 1W power amplifier (can be directly connected to external output through a resistor when not in use).

Pin description