nodemcu-firmware/docs/en/modules/i2s.md

I2S Module

Since	Origin / Contributor	Maintainer	Source
2017-04-29	zelll		i2s.c

The I2S module provides access to the in-built two I2S controllers.

i2s.start()

Configuration and start I2S bus.

Syntax

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.