Description¶

• This is a simple wave player application(not library) using PWM ports.
• This is Lite version.
  (difference from https://developer.mbed.org/users/mimi3/code/wave_player_pwm/)
• Speed up SD card accsess by modified SDFileSystem library with DMA capability.
• Only very simple User Interfaces.
• 32 step digital volume capability. (New feature)
• Variable speed functionality to play. (Up usability)
• 10bit PWM resolution quality. (Decent audio quality)
• Small code size. (About 32K byte)
• LED indicator while playing music. (New feature / (Inaccurate :D ))
• Using only passive electric components except SD card.
  ( It is needed only some resisters and capacitors )

Spec.¶

• Input data: WAVE file(PCM:*.wav files). ( must be converted by foobar2000)
• Data length: 16bit, 8bit.
• fs : ... 32kHz,44.1kHz,48kHz.
• Channel: Stereo, mono
• Output data: PWM 10bit resolutuon.
  fs and Channels are the same as input data.

Board¶

• NUCLEO-F030R8 only at this moment.
  https://developer.mbed.org/platforms/ST-Nucleo-F030R8/

Using Library¶

• SDFileSystemDMA
  https://developer.mbed.org/users/mimi3/code/SDFileSystemDMA/
  Added DMA access capability.
• FastPWM
  http://developer.mbed.org/users/Sissors/code/FastPWM/

Terminal base CUI¶

UART Terminal (e.g. Tera Term) base operation,

Tera Tem settings¶

• Serial om port: Baudrate 115200bps.
• Main Menu - [Setup] - [Terminal] dialog:

New-line settings.

Operation¶

Playing music¶

Now You can hear the sound from PWM port of mbed board.

Music01: Serenity

Music02: About That Oldie

Music03: Gemini Robot