i2s docs

docs/en/modules/i2s.md

@@ -1,6 +1,97 @@
 # I2S Module
 | Since  | Origin / Contributor  | Maintainer  | Source  |
 | :----- | :-------------------- | :---------- | :------ |
-| 2017-04-29 | | | [i2s.c](../../../components/modules/i2s.c)|
+| 2017-04-29 | zelll | | [i2s.c](../../../components/modules/i2s.c)|
 
-The I2S module provides access to the in-built I2S.
+The I2S module provides access to the in-built two I2S controllers.
+
+  
+## i2s.start()
+Configuration and start I2S bus.
+
+#### Syntax
+```lua
+i2s.start(i2s_num, cfg = {
+	mode = can.MODE_MASTER + can.MODE_TX,
+	rate = 44100,
+	bits = 16,
+	channel = i2s.CHANNEL_RIGHT_LEFT,
+	format = i2s.FORMAT_I2S + i2s.FORMAT_I2S_MSB,
+	buffer_count = 2,
+	buffer_len = 441,
+	bck_pin = 16,
+	ws_pin = 17,
+	data_out_pin = 18,
+	data_in_pin = -1
+}, callback)
+```
+
+#### Parameters
+- `i2s_num` `1` or `2`
+- `cfg` configuration
+  - `mode` combine of following constants `i2s.MODE_MASTER`, `i2s.MODE_SLAVE`, `i2s.MODE_TX`, `i2s.MODE_RX`, `i2s.MODE_DAC_BUILT_IN`. Default: `i2s.MODE_MASTER + i2s.MODE_TX`
+  - `rate` Audio sample rate, such as `44100`, `48000`, `16000`, `800`. Default: `44100`
+  - `bits` `32`, `24`, `16` or `8`. Default: `16`
+  - `channel` One of following constants. Default: `i2s.CHANNEL_RIGHT_LEFT`
+    - `i2s.CHANNEL_RIGHT_LEFT`
+	- `i2s.CHANNEL_ALL_LEFT`
+	- `i2s.CHANNEL_ONLY_LEFT`
+	- `i2s.CHANNEL_ALL_RIGHT`
+	- `i2s.CHANNEL_ONLY_RIGHT`
+  - `format` combine of following constants `i2s.FORMAT_I2S`, `i2s.FORMAT_I2S_MSB`, `i2s.FORMAT_I2S_LSB`, `i2s.FORMAT_PCM`, `i2s.FORMAT_PCM_SHORT`, `i2s.FORMAT_PCM_LONG`.
+      Default: `i2s.FORMAT_I2S + i2s.FORMAT_I2S_MSB`
+  - `buffer_count` Buffer count. Default: 2
+  - `buffer_len` Size of one buffer. Default: rate/100
+  - `bck_pin` Clock pin. Default: `-1`
+  - `ws_pin` WS pin. Default: `-1`
+  - `data_out_pin` Pin for data output. Default: `-1`
+  - `data_in_pin` Pin for data input. Default: `-1`
+- `callback` function called when i2s event occurs.
+  - `event` Event type, one of `sent`, `data`, `error`
+  - `size` bytes
+
+#### Returns
+nil
+
+
+## i2s.stop()
+Stop I2S bus
+
+#### Syntax
+`i2s.stop(i2s_num)`
+
+#### Parameters
+- `i2s_num` `1` or `2`
+
+#### Returns
+nil
+
+
+## i2s.read()
+Read data from data-in
+
+#### Syntax
+`i2s.read( i2s_num, size[, wait_ms] )`
+
+#### Parameters
+- `adc_number` Only `adc.ADC1` now
+- `size` Bytes to read
+- `wait_ms` Millisecond to wait if data is not ready. Default: `0` (not to wait)
+
+#### Returns
+Data read from data-in pin. If data is not ready in `wait_ms` millisecond, less than `size` bytes can be returned.
+
+
+## i2s.write()
+Write to I2S bus
+
+#### Syntax
+`i2s.write( i2s_num, size[, wait_ms] )`
+
+#### Parameters
+- `adc_number` Only `adc.ADC1` now
+- `size` Bytes to send
+- `wait_ms` Millisecond to wait if DMA buffer is full. Default: `0` (not to wait)
+
+#### Returns
+Integer, bytes wrote to buffer.