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19 мая
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Alex B. (08.07.2008 23:27, просмотров: 2545)
Microchip выпустил библиотеку Audio Library для PIC32 http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en534485
- Portable across all 32-bit family of microcontrollers. - Functions independently of RTOS or application - Supports Microchip’s MPLAB® C32 compiler - Implements an audio player behavior with play, record, pause, stop functionality. - Supported encoding formats: PCM (raw, uncompressed), IMA ADPCM, Speex. - Supports standard input/output stream formats: Wave, Ogg for Speex, as well as a free format, containing just data. - Supports DMA transfers and interrupt driven operation for minimizing the library overhead. Both the interrupts and the DMA are highly configurable both at build and run time. - Supports various sampling rates in both play and record mode. The sampling rate is dynamically selectable. - Flexible data manipulation for both play and record operation. The user provides call back functions to provide/store the data. - Dynamic configuration of the buffers used for encoding/decoding. Depending on the sampling rate, the user can trim the buffers used internally by the Audio Library, resulting in different overhead for the main application. - User selectable ratio between the sampling frequency and the play/record frequency. - Little/big endian support for playing/recording ADPCM data. - Provides information about the missed samples. When playing, a missed beat usually indicates that the read data call back is too slow. Similarly, when recording, missed beats mean that the write data call back was too slow. User can adjust accordingly. - Flexible, user defined call backs for playing a sample to the output device or for reading a sample from an input device. - Different functions for initialization, clean up, enabling/disabling in/out stages, samples processing, etc. are provided. - Default input and output devices and supporting functions are provided. - Flexibility of choosing the desired sampling device at run time (i.e. an interrupt vector and ipl) without the need to re-build the audio library.
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