i2s - Digital Audio#

Adapted Air780E/Air700E Air780EP Air601 Air101/Air103

Note

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Tip

This library has its own demo,click this link to view the demo example of i2s

Example

-- This library belongs to the underlying adaptation library, please refer to the example for specific usage.
-- demo/multimedia
-- demo/tts
-- demo/record

Constant#

constant	type	explanation
i2s.MODE_I2S	number	I2S Standards, such ES7149
i2s.MODE_LSB	number	LSB Format
i2s.MODE_MSB	number	MSB format, such TM8211
i2s.MONO_L	number	Left channel
i2s.MONO_R	number	Right Channel
i2s.STEREO	number	Stereo

i2s.setup(id, mode, sample, bitw, channel, format, framebit)#

Initialization i2s

Parameters

Incoming Value Type	Explanation
int	i2s Channel number, related to specific equipment
int	Mode, 0 master 1 slave
int	Sampling rate, default 44100. Optional
int	Number of data bits, default 16, can be a multiple of 8
int	Channel, 0 left channel, 1 right channel, 2 stereo. Optional
int	format, optional MODE_I2S, MODE_LSB, MODE_MSB
int	1 BCLK number of channels, optional 16 and 32

Return Value

return value type	explanation
boolean	Success or not
int	underlying return value

Examples

-- Initialize with default parameters i2s
i2s.setup(0)
-- Initialize i2s with detailed parameters, example with default values
i2s.setup(0, 0, 44100, 16, 0, 0, 16)

i2s.send(id, data, len)#

Send i2s data

Parameters

Incoming Value Type	Explanation
int	Channel id
string	Data, which can be a string or zbuff
int	Data length, unit byte, string is the full length of the string by default, zbuff is the pointer position by default

Return Value

return value type	explanation
boolean	Success or not
int	The underlying return value, for debugging trial

Examples

local f = io.open("/luadb/abc.wav")
while 1 do
    local data = f:read(4096)
    if not data or #data == 0 then
        break
    end
    i2s.send(0, data)
    sys.wait(100)
end

i2s.recv(id, buffer, len)#

Receive i2s data, note that the data has been stored in zbuff at the time of callback, currently only air780e series support

Parameters

Incoming Value Type	Explanation
int	Channel id
zbuff	Data cache
int	The length of the data returned at a time, in bytes, must be consistent with the size of the zbuff passed in.

Return Value

return value type	explanation
boolean	Success or not

Examples

local buffer = zbuff.create(3200)
local succ = i2s.recv(0, buffer, 3200);

i2s.close(id)#

Close i2s

Parameters

Incoming Value Type	Explanation
int	Channel id

Return Value

return value type	explanation
nil	No return value

Examples

i2s.close(0)

i2s.on(id, func)#

Parameters

Incoming Value Type	Explanation
int	i2s id, i2s0 Write 0, i2s1 write 1
function	Callback Method

Return Value

return value type	explanation
nil	No return value

Examples

i2s.on(0, function(id, buff)
    if buff then
        log.info("i2s get data in zbuff")
    else
        log.info("i2s tx one block done")
    end
end)

i2s.txStat(id)#

Get the send buffer status for i2s

Parameters

Incoming Value Type	Explanation
int	i2s id, i2s0 Write 0, i2s1 write 1
return	Total size of the underlying buffer
return	Remaining data to be sent in the underlying buffer

Return Value

None

Examples

-- Read the status of the send buffer to determine whether incoming audio data needs to continue
local max, remain = i2s.txStat(0)
log.info("i2s Send Buffer Status", max, remain)

i2s.getPara(id)#

Obtain the I2S parameter. For more information, see setup

Parameters

Incoming Value Type	Explanation
int	Channel id

Return Value

return value type	explanation
boolean	Is true in working state
int	Mode, 0 master 1 slave
int	Sample Rate
int	Number of data bits
int	vocal tract
int	Format
int	1 BCLK number of channels

Examples

None