1, VS1003: VS1003 audio decoding format: MP3, MP3 + V, WMA, WAV, MIDI, SP-MIDI; recording encoding format: IMA ADPCM (monaural), microphone and line-in (Line input) two input methods; supports MP3 and WAV stream; low-power; internal PLL clock frequency multiplier; quality stereo digital-to-analog converter (DAC); 16-bit high-quality stereo adjustable on-chip analog-to-digital converter (ADC); the earplugs driver (30 euro); separate analog, digital, and IO power supply; serial data and control interface (SPI);
2,SPI interface, the control signal line leads
3,1 headphones and audio output interface
4,1 microphone for recording
5,1 line_in input interface 6, the power indicator
7, on-board 3.3V and 2.5V LDO 1117, the largest provider of 800mA current
8, a single power supply: +5 VDC, capacitor filter
9,12.288 MHz crystal oscillator
10, PCB size: 50x40.5 mm