WT2003HM01 Voice Module
Compact UART‑Controlled Voice Module with Built‑in 32Mbit Flash & 0.5W Amp
The WT2003HM01 is a compact, high‑performance voice module featuring built‑in 32Mbit Flash for immediate voice storage without external components. Powered by a 32‑bit processor up to 120MHz, it supports external SPI‑Flash and USB drive expansion for flexible audio content management. With 32‑level volume control, a built‑in 0.5W Class‑D amplifier, and a simple UART command set (default 9600 baud), it is ideal for voice prompt systems, home appliances, and industrial equipment.
- 32‑bit processor – 120MHz for smooth playback
- Built‑in 32Mbit Flash – ready‑to‑use storage
- UART control – simple serial commands
- Built‑in 0.5W amp – direct speaker drive
- 32‑level volume – with power‑off memory
Key Features
UART Command Set
| Command | Function | Description |
|---|---|---|
| A0 | SPI‑Flash Index Playback | Play audio by index in SPI‑Flash root |
| A1 | SPI‑Flash Filename Playback | Play audio by filename in SPI‑Flash root (4‑byte name) |
| A6 | USB Index Playback | Play audio by index in USB drive root |
| A7 | USB Filename Playback | Play audio by filename in USB drive root (4‑byte name) |
| A8 | USB Folder Index Playback | Play audio by index in USB folder (5‑char folder name) |
| A9 | USB Folder Filename Playback | Play audio by filename in USB folder |
| AA | Pause / Resume | Toggle pause/playback |
| AB | Stop | Stop current playback |
| AC | Next Track | Play next track |
| AD | Previous Track | Play previous track |
| AE | Volume Control | Set volume (0–31, with power‑off memory) |
| AF | Playback Mode | Normal / Single loop / All loop / Random |
| B1 | Insert Playback | Insert a track during current playback |
| B6 | Output Mode Switch | Switch between PWM (SPK) and DAC |
| C1 | Query Volume | Read current volume level |
| C2 | Query Work Status | Play / Stop / Pause |
| C3 | Query SPI‑Flash File Count | Get total audio files in SPI‑Flash |
| C7 | Query USB File Count | Get total audio files in USB drive |
| C8 | Query USB Folder File Count | Get audio file count in USB folder |
| C9 | Query Current Track | Get current playback track address |
| CA | Query Peripheral Status | Check Flash, USB, and PC connection status |
| CB | Query Current Song Name | Get filename of current playback |
Protocol format: 7E + Length + Command + Parameters + Checksum + EF. Checksum is the low byte of (Length + Command + Parameters) sum.
Technical Specifications
| Parameter | Value / Condition |
|---|---|
| Processor | 32‑bit, up to 120MHz |
| Operating Voltage | 2.6V – 5.0V (ripple <5%, peak <5.5V) |
| Built‑in Flash | 32 Mbit |
| External SPI‑Flash | Up to 128Mbit (FAT/FAT32) |
| USB Drive | Up to 32GB (FAT/FAT32) |
| Audio Formats | MP3, WAV (8–320kbps) |
| Audio Output | PWM (0.5W Class‑D) / DAC |
| Volume Levels | 32 (0–31, with power‑off memory) |
| Playback Modes | Normal, Single loop, All loop, Random |
| Control Interface | UART (default 9600 baud) |
| Peripherals | I2C, PWM, Infrared decoder, 16‑bit ADC/DAC |
| IO Drive Capability | Up to 64mA |
| Operating Temperature | ‑40°C ~ +85°C |
| Module Size | 21.01 × 18.21mm |
| Pin Pitch | 2.0mm |
Key Pin Functions (20‑Pin Module)
| Pin | Name | Function |
|---|---|---|
| 2 | VBAT | Power input (2.6–5.0V) |
| 3 | TXD | UART transmit |
| 4 | RXD | UART receive |
| 5 | BUSY | Busy signal output (high during playback) |
| 6 | ADKEY | Analog key input |
| 7 | SPK+ | Speaker positive terminal |
| 8 | SPK− | Speaker negative terminal |
| 9/10 | DAC | DAC audio output (mono) |
| 11 | DM | USB D− |
| 12 | DP | USB D+ |
| 13 | SD_DAT / SPI_CS | SD card data / SPI‑Flash chip select |
| 14 | SD_CMD / SPI_DAT | SD card command / SPI‑Flash data |
| 15 | SD_CLK / SPI_CLK | SD card clock / SPI‑Flash clock |
| 16 | VDDIO | 3.3V power output |
| 19 | AGND | Analog ground |
| 20 | ONEKEY | Next track button |
Application Scenarios
Why Choose WT2003HM01
Frequently Asked Questions
What is the WT2003HM01 voice module?
WT2003HM01 is a compact voice playback module featuring a 32-bit processor (up to 120MHz), built-in 32Mbit Flash, UART serial control, SPI-Flash and USB storage support, built-in 0.5W amplifier, and 32-level volume control.
What storage options are available?
WT2003HM01 features built-in 32Mbit Flash, supports external SPI-Flash up to 128Mbit, and USB drives up to 32GB. The built-in Flash provides immediate storage without external components.
How do I control the module?
The WT2003HM01 module uses a standard UART serial interface with default baud rate 9600. Commands follow a 7E … EF protocol for playback, volume, mode, and query operations.
Does it have a built-in amplifier?
Yes. WT2003HM01 features a built-in 0.5W Class-D amplifier with PWM output. DAC output is also available with a command switch (B6).
How many volume levels are available?
32 levels (0 to 31), with 0 = mute and 31 = maximum volume. The setting has power-off memory.
What is the operating voltage range?
The module operates from 2.6V to 5.0V, with ripple controlled within 5% and peak voltage below 5.5V.
What is the module size?
The module measures 21.01mm × 18.21mm with 2.0mm pin spacing, making it suitable for compact designs.
Can I update audio files via USB?
Yes. Connect the module to a PC via USB, and the Flash storage appears as a removable drive. Copy audio files directly, then disconnect USB before sending serial commands.
What audio formats are supported?
It supports MP3 and WAV formats with bitrates from 8kbps to 320kbps, delivering high-quality audio playback.
What are the typical applications?
Voice prompt systems, home appliances, automotive electronics, toys, industrial alarms, consumer electronics, and any application requiring compact voice playback with built-in storage.
Important: The module supports FAT and FAT32 formats only. For external SPI‑Flash, Waytronic‑branded Flash is recommended for guaranteed compatibility. After copying audio files via USB, disconnect the USB cable before sending UART commands. The BUSY pin is low in idle and high during playback. When switching audio output modes (B6), wait 200ms before sending other commands. The built‑in 32Mbit Flash provides immediate voice storage out‑of‑the‑box.
