How to Use WTV020 Micro SD Card: Examples, Pinouts, and Specs

The WTV020 Micro SD Card is a compact audio playback module designed for storing and playing audio files from a Micro SD card. It supports multiple audio formats, including AD4 and WAV, making it ideal for projects requiring sound output. This module is widely used in applications such as toys, alarms, interactive devices, and embedded systems where audio feedback or sound effects are needed. Its small size and ease of integration make it a popular choice for hobbyists and professionals alike.

• Operating Voltage: 2.6V to 3.6V DC
• Current Consumption: < 15mA during playback
• Audio Formats Supported: AD4, WAV
• Storage Medium: Micro SD card (up to 2GB, FAT16 format)
• Output Modes:
  • DAC output for direct speaker connection
  • PWM output for external amplifier
• Control Interface: Serial communication (UART or GPIO control)
• Dimensions: 20mm x 18mm x 8mm

The WTV020 module has 8 pins. Below is the pinout and description:

1. Power Supply: Connect the VCC pin to a 3.3V power source and the GND pin to ground. Ensure the power supply is stable to avoid malfunctions.
2. Micro SD Card Preparation:
   • Format the Micro SD card to FAT16.
   • Convert audio files to AD4 format using the WTV020 conversion tool.
   • Copy the AD4 files to the root directory of the Micro SD card.
3. Speaker Connection:
   • For direct speaker output, connect the SPK+ and SPK- pins to a small 8-ohm speaker.
   • For higher power output, use the PWM output with an external amplifier.
4. Control Interface:
   • Use the RX pin to send commands via UART or GPIO to control playback.
   • Monitor the BUSY pin to check playback status.

• Voltage Levels: Ensure the module operates within the specified voltage range (2.6V to 3.6V). Exceeding this range may damage the module.
• File Format: Only AD4 files are supported for playback. Use the official WTV020 conversion tool to convert audio files.
• Micro SD Card Compatibility: Use a Micro SD card with a capacity of 2GB or less, formatted to FAT16. Larger cards or other formats may not work.
• Decoupling Capacitor: Add a 10µF capacitor between VCC and GND to stabilize the power supply.
• UART Communication: If using UART, ensure the baud rate is set to 9600 bps.

Below is an example of how to control the WTV020 module using an Arduino UNO:

#include <SoftwareSerial.h>

// Define RX and TX pins for SoftwareSerial
SoftwareSerial wtv020Serial(10, 11); // RX = Pin 10, TX = Pin 11

void setup() {
  wtv020Serial.begin(9600); // Initialize serial communication at 9600 bps
  pinMode(8, OUTPUT);       // Set pin 8 as output for module power control
  digitalWrite(8, HIGH);    // Power on the WTV020 module
  delay(100);               // Wait for the module to initialize
}

void loop() {
  playAudio(0x01);          // Play the first audio file
  delay(5000);              // Wait for 5 seconds
  playAudio(0x02);          // Play the second audio file
  delay(5000);              // Wait for 5 seconds
}

// Function to send play command to WTV020
void playAudio(byte trackNumber) {
  wtv020Serial.write(0xFF); // Start byte
  wtv020Serial.write(0x06); // Play command
  wtv020Serial.write(0x00); // Data length
  wtv020Serial.write(0x00); // High byte of track number
  wtv020Serial.write(trackNumber); // Low byte of track number
  wtv020Serial.write(0xEF); // End byte
}

1. No Sound Output:

   • Ensure the Micro SD card is formatted to FAT16 and contains valid AD4 files.
   • Check the speaker connections (SPK+ and SPK-).
   • Verify the power supply voltage is within the specified range.

2. Module Not Responding:

   • Confirm the RX and TX connections are correct.
   • Ensure the baud rate is set to 9600 bps if using UART.
   • Check if the PWR pin is set HIGH to enable the module.

3. Playback Stops Abruptly:

   • Verify the BUSY pin status to ensure the module is not interrupted.
   • Check the power supply for stability and add a decoupling capacitor if needed.

4. Micro SD Card Not Detected:

   • Use a Micro SD card with a capacity of 2GB or less.
   • Ensure the card is properly inserted and formatted to FAT16.

• Q: Can I use a Micro SD card larger than 2GB?
  A: No, the WTV020 module only supports Micro SD cards up to 2GB formatted to FAT16.

• Q: What is the maximum speaker power output?
  A: The module can drive small 8-ohm speakers directly, but for higher power, use an external amplifier.

• Q: Can I control the module without UART?
  A: Yes, the module can also be controlled using GPIO pins for basic playback functions.

• Q: How do I convert audio files to AD4 format?
  A: Use the official WTV020 conversion tool, which is available online, to convert WAV or MP3 files to AD4 format.

By following this documentation, you can effectively integrate the WTV020 Micro SD Card module into your projects and troubleshoot common issues.