2017-04-28 22:27:57 +02:00
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# I2S Module
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| Since | Origin / Contributor | Maintainer | Source |
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| :----- | :-------------------- | :---------- | :------ |
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2017-04-29 19:07:46 +02:00
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| 2017-04-29 | zelll | | [i2s.c](../../../components/modules/i2s.c)|
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2017-04-28 22:27:57 +02:00
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2017-04-29 19:07:46 +02:00
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The I2S module provides access to the in-built two I2S controllers.
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## i2s.start()
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Configuration and start I2S bus.
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#### Syntax
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```lua
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i2s.start(i2s_num, cfg = {
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mode = can.MODE_MASTER + can.MODE_TX,
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rate = 44100,
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bits = 16,
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channel = i2s.CHANNEL_RIGHT_LEFT,
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format = i2s.FORMAT_I2S + i2s.FORMAT_I2S_MSB,
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buffer_count = 2,
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buffer_len = 441,
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bck_pin = 16,
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ws_pin = 17,
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data_out_pin = 18,
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data_in_pin = -1
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}, callback)
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```
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#### Parameters
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- `i2s_num` `1` or `2`
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- `cfg` configuration
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- `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`
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- `rate` Audio sample rate, such as `44100`, `48000`, `16000`, `800`. Default: `44100`
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- `bits` `32`, `24`, `16` or `8`. Default: `16`
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- `channel` One of following constants. Default: `i2s.CHANNEL_RIGHT_LEFT`
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- `i2s.CHANNEL_RIGHT_LEFT`
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- `i2s.CHANNEL_ALL_LEFT`
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- `i2s.CHANNEL_ONLY_LEFT`
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- `i2s.CHANNEL_ALL_RIGHT`
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- `i2s.CHANNEL_ONLY_RIGHT`
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- `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`.
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Default: `i2s.FORMAT_I2S + i2s.FORMAT_I2S_MSB`
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- `buffer_count` Buffer count. Default: 2
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- `buffer_len` Size of one buffer. Default: rate/100
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- `bck_pin` Clock pin. Default: `-1`
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- `ws_pin` WS pin. Default: `-1`
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- `data_out_pin` Pin for data output. Default: `-1`
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- `data_in_pin` Pin for data input. Default: `-1`
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- `callback` function called when i2s event occurs.
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- `event` Event type, one of `sent`, `data`, `error`
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- `size` bytes
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#### Returns
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nil
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## i2s.stop()
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Stop I2S bus
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#### Syntax
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`i2s.stop(i2s_num)`
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#### Parameters
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- `i2s_num` `1` or `2`
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#### Returns
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nil
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## i2s.read()
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Read data from data-in
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#### Syntax
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`i2s.read( i2s_num, size[, wait_ms] )`
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#### Parameters
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- `adc_number` Only `adc.ADC1` now
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- `size` Bytes to read
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- `wait_ms` Millisecond to wait if data is not ready. Default: `0` (not to wait)
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#### Returns
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Data read from data-in pin. If data is not ready in `wait_ms` millisecond, less than `size` bytes can be returned.
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## i2s.write()
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Write to I2S bus
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#### Syntax
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`i2s.write( i2s_num, size[, wait_ms] )`
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#### Parameters
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- `adc_number` Only `adc.ADC1` now
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- `size` Bytes to send
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- `wait_ms` Millisecond to wait if DMA buffer is full. Default: `0` (not to wait)
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#### Returns
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Integer, bytes wrote to buffer.
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