This is Altera Avalon IP core for TI TLV320AIC1106 PCM Codec With Microphone Amps & Speaker Driver.
The AIC1106 IP core receive/transmit audio data from/to CPU with standard Avalon staream sink/source. Also the IP core have mode/status register implemented as Avalon memory mapped register.
Format of the mode/status register:
Read:
| 31..6 | 5 | 4 | 3 | 2 | 1..0 |
|---|---|---|---|---|---|
| 0 | underflow_r | mute | reset_n | 0 | volume |
Write:
| 31..6 | 5 | 4 | 3 | 2 | 1..0 |
|---|---|---|---|---|---|
| 0 | reset | loopback | enable | mute | volume |
Normally, the stream sink/source interface should be connected to separate FIFO buffers implemented as on-chip FIFO memory. The FIFO buffer, in turn, is connected to the system bus of the processor.
When FIFO buffers near to full/empty it fire interrupt and software driver is responsible for read/write FIFO buffers to keep audio staream continuouse.
During driver initialization, it registered as new device /mnt/audio/ and being accessible as regular file.
Driver also capable to read/write standard .wav file.
For details, please explore files audio_drv.c and audio_drv.h