Component: WAV Library File (Storage)

Author	Matrix TSL
Version	1.0
Category	Storage

WAV Library File component

Allows WAV files to be played or recorded using a file component to provide the data. Complete with buffer to allow for uninterrupted playback when performing other tasks. Playback compatible with analogue outputs such as DAC or PWM. Recording compatible with analogue inputs such as a Microphone.

Component Pack

STORAGE

Detailed description

No detailed description exists yet for this component

Examples

Simple playback example - allows a wav file to be streamed out using PWM. Repeats the playback in a loop.

WAV Playback

Simple recording example - allows a wav file to be recorded from a microphone connected to an ADC input pin. Records for approx 10 seconds.

WAV Record

Downloadable macro reference

	StartPlayback
Start playing a WAV file from the SD card. Use the GetNextSample and EndOfFile macros to read out the contents of the file. Use the ProcessBuffer macro to maintain the local buffer. Returns 1 if file found and opened, else returns 0.
- STRING	Filename
WAV Filename e.g. "Test.wav"
- BYTE	Return

	EndOfFile
A simple check to see if we are at the end of the file. Returns 0 if we and not yet at the end fo the file. Returns 1 if we are at the end of the file.
- BOOL	Return

	ProcessBuffer
When Playing a WAV File - Fills the local data buffer from the SD card. When Recording a WAV File - Writes the local data buffer to the SD card. Must be called often enough to maintain playback or recording. Returns 0 for buffer OK 1 for buffer overrun
- BYTE	Return

	StopRecording
- VOID	Return

	PutNextSample
Writes the value for the next sample and auto increments the file pointer. Ideally this function should be called as part of a timer interrupt at the sample rate. The value written should be collected using an analogue input such as a Mic.
- UINT	Sample
- VOID	Return

	GetNumChannels
Returns the number of audio channels stored in the WAV file during playback.
- BYTE	Return

	StartRecording
Start recording a WAV file to the SD card. Use the WritetNextSample macro to write the contents of the file. Use the ProcessBuffer macro to maintain the local buffer. Returns 1 if file created and opened, else returns 0.
- STRING	Filename
WAV Filename e.g. "Test.wav"
- BYTE	BitsPerSample
Number of bits per sample - 8 or 16
- ULONG	SampleRate
Sample Rate in Hz e.g. 8000 for 8KHz
- BYTE	Return

	GetBitsPerSample
Returns the number of bits per sample during playback.
- BYTE	Return

	GetNextSample
Retreives the value for the next sample and auto increments the file pointer. Ideally this function should be called as part of a timer interrupt at the sample rate. The value returned should be passed onto a means of analogue output e.g. a DAC or PWM.
- UINT	Return

Property reference

	Properties
	File Component
Pointer to the File component in your program that is responsible for providing the data to stream.
	Buffer Size
The number of RAM bytes to allocate to the WAV buffer. The buffer must be big enough to store enough WAV audio samples to maintain playback or recording when doing other program tasks or performing SD card read/write operations.
	Memory Type