Audio controller (I2S, SPDIF, DAC)
Github: https://github.com/ultraembedded/core_audio
This component is a basic audio controller providing I2S, SPDIF, and DAC outputs.
Simple to drive AXI4-L register interface, with built in 2048 entry buffer and interrupt on programmable threshold.
Features
- SPDIF transmitter supporting 16-bit sample width @ 44.1KHz or 48KHz.
- I2S master (SCK, SDATA, WS).
- 2 channel sigma delta DAC outputs.
- AXI4-L register interface.
- 8KB RAM buffer inferred (maps blockRAM on Xilinx) (2048 x 16-bit x 2).
- Programmable interrupt threshold.
- Single interrupt output.
Instance
- Top: audio
- Clock: clk_i
- Reset: rst_i - Asynchronous, active high
Register Map
| Offset | Name | Description |
|---|---|---|
| 0x00 | AUDIO_CFG | [RW] Configuration Register |
| 0x04 | AUDIO_STATUS | [R] UART Status Register |
| 0x08 | AUDIO_CLK_DIV | [RW] Clock divisor |
| 0x0c | AUDIO_CLK_FRAC | [RW] Clock divisor (fractional part) |
| 0x20 | AUDIO_FIFO_WRITE | [W] Audio data write FIFO |
Register: AUDIO_CFG
| Bits | Name | Description |
|---|---|---|
| 15:0 | INT_THRESHOLD | Buffer low watermark interrupt threshold |
| 16 | BYTE_SWAP | Byte order swap on buffer write |
| 17 | CH_SWAP | Channel swap |
| 19:18 | TARGET | 0=I2S,1=SPDIF,2=DAC |
| 26:24 | VOL_CTRL | Volume control (0 = max, 7 = min) |
| 31 | BUFFER_RST | Flush audio buffer |
Register: AUDIO_STATUS
| Bits | Name | Description |
|---|---|---|
| 31:16 | LEVEL | FIFO level |
| 1 | FULL | Buffer full |
| 0 | EMPTY | Buffer empty |
Register: AUDIO_CLK_DIV
| Bits | Name | Description |
|---|---|---|
| 15:0 | WHOLE_CYCLES | Number of whole cycles to divide clk by (clk_out = clk/(whole_cycles+1)) |
Register: AUDIO_CLK_FRAC
| Bits | Name | Description |
|---|---|---|
| 15:0 | NUMERATOR | Fractional clock divider numerator |
| 31:16 | DENOMINATOR | Fractional clock divider denominator |
Register: AUDIO_FIFO_WRITE
| Bits | Name | Description |
|---|---|---|
| 15:0 | CH_B | Channel B audio sample write |
| 31:16 | CH_A | Channel A audio sample write |