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micropython/docs/library/wm8960.rst

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drivers/codec: Add driver for the WM8960 codec. This codec is assembled for the MIMXRT1xxx_DEV boards and available for WM8960 breakout boards as well. The driver itself has been tested as working with the MIMXRT boards and a Sparkfun WM6890 breakout board. It implements the initialization, basic methods and some enhanced methods like 3D, ALC, soft-mute and deemphasis.
2022-02-10 12:51:48 +00:00
.. _wm8960:
:mod:`WM8960` -- Driver for the WM8960 codec
============================================
This driver is used to control a WM8960 codec chip. It is a Python
translation of the C-Code provided by NXP/Freescale for their i.MX RT series of
MCUs. Very little has been added, and just a few API related names were changed
or added to cope with the naming style of MicroPython.
The primary purpose of the driver is initialization and setting operation modes
of the codec. It does not do the audio data processing for the codec. That is
the task of a separate driver.
The WM8960 supports an I2C interface, in addition to the audio interface. The
connection depends on the interface used and the number of devices in the
system. For the I2C interface, SCL and SDA have to be connected, and of course
GND and Vcc. The I2C default address is ``0x1A``.
Constructor
-----------
.. class:: WM8960(i2c, sample_rate, *, bits=16, swap=SWAP_NONE, route=ROUTE_PLAYBACK_RECORD, left_input=INPUT_MIC3, right_input=INPUT_MIC2, sysclk_source=SYSCLK_MCLK, mclk_freq=None, primary=False, adc_sync=SYNC_DAC, protocol=BUS_I2S, i2c_address=WM8960_I2C_ADDR)
Create a WM8960 driver object, initialize the device with default settings and return the
WM8960 object.
Only the first two arguments are mandatory. All others are optional. The arguments are:
- *i2c* is the I2C bus object.
- *sample_rate* is the audio sample rate. Acceptable values are 8000,
11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000, 96000, 192000
and 384000. Note that not every I2S hardware will support all values.
- *bits* is the number of bits per audio word. Acceptable value are 16,
20, 24, and 32.
- *swap* swaps the left & right channel, if set; see below for options.
- *route* Setting the audio path in the codec; see below for options.
- *left_input* sets the audio source for the left input channel;
see below for options.
- *right_input* sets the audio source for the right input channel;
see below for options.
- *play_source* sets the audio target for the output audio;
see below for options.
- *sysclk_source* controls whether the internal master clock called
"sysclk" is directly taken from the MCLK input or derived from it
using an internal PLL. It is usually not required to change this.
- *mclk_freq* sets the mclk frequency applied to the MCLK pin of the
codec. If not set, default values are used.
- *primary* lets the WM8960 act as primary or secondary device. The
default setting is ``False``. When set to ``False``,
*sample_rate* and *bits* are controlled by the MCU.
- *adc_sync* sets which input is used for the ADC sync signal.
The default is using the DACLRC pin.
- *protocol* sets the communication protocol. The default is I2S.
See below for all options.
- *i2c_address* sets the I2C address of the WM8960, with default ``0x1A``.
If *mclk_freq* is not set the following default values are used:
- sysclk_source == SYSCLK_PLL: 11.2896 MHz for sample rates of 44100,
22050 and 11015 Hz, and 12.288 Mhz for sample rates < 48000, otherwise
sample_rate * 256.
- sysclk_source == SYSCLK_MCLK: sample_rate * 256.
If the MCLK signal is applied using, for example,. a separate oscillator,
it must be specified for proper operation.
Tables of parameter constants
-----------------------------
.. table:: **Swap Parameter**
:widths: auto
:align: left
===== ====
Value Name
===== ====
0 SWAP_NONE
1 SWAP_INPUT
2 SWAP_OUTPUT
===== ====
.. table:: **Protocol Parameter**
:widths: auto
:align: left
===== ====
Value Name
===== ====
2 BUS_I2S
1 BUS_LEFT_JUSTIFIED
0 BUS_RIGHT_JUSTIFIED
3 BUS_PCMA
19 BUS_PCMB
===== ====
.. table:: **Input Source Parameter**
:widths: auto
:align: left
===== ============ ====
Value Name Type
===== ============ ====
0 INPUT_CLOSED
1 INPUT_MIC1 Single ended
2 INPUT_MIC2 Differential
3 INPUT_MIC3 Differential
4 INPUT_LINE2
5 INPUT_LINE3
===== ============ ====
.. table:: **Route Parameter**
:widths: auto
:align: left
===== ====
Value Name
===== ====
0 ROUTE_BYPASS
1 ROUTE_PLAYBACK
2 ROUTE_PLAYBACK_RECORD
5 ROUTE_RECORD
===== ====
.. table:: **Master Clock Source Parameter**
:widths: auto
:align: left
===== ====
Value Name
===== ====
0 SYSCLK_MCLK
1 SYSCLK_PLL
===== ====
.. table:: **Module Names**
:widths: auto
:align: left
===== ====
Value Name
===== ====
0 MODULE_ADC
1 MODULE_DAC
2 MODULE_VREF
3 MODULE_HEADPHONE
4 MODULE_MIC_BIAS
5 MODULE_MIC
6 MODULE_LINE_IN
7 MODULE_LINE_OUT
8 MODULE_SPEAKER
9 MODULE_OMIX
10 MODULE_MONO_OUT
===== ====
.. table:: **Play Channel Names**
:widths: auto
:align: left
===== ====
Value Name
===== ====
1 PLAY_HEADPHONE_LEFT
2 PLAY_HEADPHONE_RIGHT
4 PLAY_SPEAKER_LEFT
8 PLAY_SPEAKER_RIGHT
===== ====
.. table:: **adc_sync Parameters**
:widths: auto
:align: left
===== ====
Value Name
===== ====
0 SYNC_ADC
1 SYNC_DAC
===== ====
Methods
-------
In addition to initialization, the driver provides some useful methods for
controlling its operation:
.. method:: WM8960.set_left_input(input_source)
Specify the source for the left input. The input source names are listed above.
.. method:: WM8960.set_right_input(input_source)
Specify the source for the right input. The input source names are listed above.
.. method:: WM8960.volume(module, volume_l=None, volume_r=None)
Sets or gets the volume of a certain module.
If no volume values are supplied, the actual volume tuple is returned.
If one or two values are supplied, it sets the volume of a certain module.
If two values are provided, the first one is used for the left channel,
the second for the right channel. If only one value is supplied, it is used
for both channels. The value range is normalized to 0.0-100.0 with a
logarithmic scale.
For a list of suitable modules and db/step, see the table below.
.. table:: **Module Names and dB steps**
:widths: auto
:align: center
======= ====
dB/Step Name
======= ====
1.28 MODULE_ADC
1.28 MODULE_DAC
0.8 MODULE_HEADPHONE
0.475 MODULE_LINE_IN
0.8 MODULE_SPEAKER
======= ====
.. method:: WM8960.mute(module, mute, soft=True, ramp=wm8960.MUTE_FAST)
Mute or unmute the output. If *mute* is True, the output is muted, if ``False``
it is unmuted.
If *soft* is set as True, muting will happen as a soft transition. The time for
the transition is defined by *ramp*, which is either ``MUTE_FAST`` or ``MUTE_SLOW``.
.. method:: WM8960.set_data_route(route)
Set the audio data route. For the parameter value/names, see the table above.
.. method:: WM8960.set_module(module, active)
Enable or disable a module, with *active* being ``False`` or ``True``. For
the list of module names, see the table above.
Note that enabling ``MODULE_MONO_OUT`` is different from the `WM8960.mono`
method. The first enables output 3, while the `WM8960.mono` method sends a
mono mix to the left and right output.
.. method:: WM8960.enable_module(module)
Enable a module. For the list of module names, see the table above.
.. method:: WM8960.disable_module(module)
Disable a module. For the list of module names, see the table above.
.. method:: WM8960.expand_3d(level)
Enable Stereo 3D exansion. *level* is a number between 0 and 15.
A value of 0 disables the expansion.
.. method:: WM8960.mono(active)
If *active* is ``True``, a Mono mix is sent to the left and right output
channel. This is different from enabling the ``MODULE_MONO_MIX``, which
enables output 3.
.. method:: WM8960.alc_mode(channel, mode=ALC_MODE)
Enables or disables ALC mode. Parameters are:
- *channel* enables and sets the channel for ALC. The parameter values are:
- ALC_OFF: Switch ALC off
- ALS_RIGHT: Use the right input channel
- ALC_LEFT: Use the left input channel
- ALC_STEREO: Use both input channels.
- *mode* sets the ALC mode. Input values are:
- ALC_MODE: act as ALC
- ALC_LIMITER: act as limiter.
.. method:: WM8960.alc_gain(target=-12, max_gain=30, min_gain=-17.25, noise_gate=-78)
Set the target level, highest and lowest gain levels and the noise gate as dB level.
Permitted ranges are:
- *target*: -22.5 to -1.5 dB
- *max_gain*: -12 to 30 dB
- *min_gain*: -17 to 25 dB
- *noise_gate*: -78 to -30 dB
Excess values are limited to the permitted ranges. A value of -78 or less
for *noise_gate* disables the noise gate function.
.. method:: WM8960.alc_time(attack=24, decay=192, hold=0)
Set the dynamic characteristic of ALC. The times are given as millisecond
values. Permitted ranges are:
- *attack*: 6 to 6140
- *decay*: 24 to 24580
- *hold*: 0 to 43000
Excess values are limited within the permitted ranges.
.. method:: WM8960.deemphasis(active)
Enables or disables a deemphasis filter for playback, with *active* being
``False`` or ``True``. This filter is applied only for sample rates of
32000, 44100 and 48000. For other sample rates, the filter setting
is silently ignored.
.. method:: WM8960.deinit()
Disable all modules.
Examples
--------
Run WM8960 in secondary mode (default)::
# Micro_python WM8960 Codec driver
#
# Setting the driver to Slave mode using the default settings
#
from machine import Pin, I2C
import wm8960
i2c = I2C(0)
wm=wm8960.WM8960(i2c, 32000, left_input=wm8960.INPUT_MIC1)
wm.set_volume(wm8960.MODULE_HEADPHONE, 100)
Run WM8960 in primary mode::
# Micro_python WM8960 Codec driver
#
# Setting the driver to Master mode using specific audio format settings
#
from machine import Pin, I2C
import wm8960
i2c = I2C(0)
wm=wm8960.WM8960(i2c, 44100, primary=True, bits=16)
Run WM8960 on a MIMXRT10xx_DEV board in secondary mode (default)::
# Micro_python WM8960 Codec driver
#
# Setting the driver to Slave mode using the default settings
# swap the input channels such that a MIMXRT Dev board mic, which
# is connected to the right input, is assigned to the left audio channel.
#
from machine import Pin, I2C
import wm8960
i2c = I2C(0)
wm=wm8960.WM8960(i2c, sample_rate=16_000,
adc_sync=wm8960.SYNC_DAC,
swap=wm8960.SWAP_INPUT,
sysclk_source=wm8960.SYSCLK_MCLK)
Record with a Sparkfun WM8960 breakout board with Teensy in secondary mode (default)::
# Micro_python WM8960 Codec driver
#
# The breakout board uses a fixed 24MHz MCLK. Therefore the internal
# PLL must be used as sysclk, which is the master audio clock.
# The Sparkfun board has the WS pins for RX and TX connected on the
# board. Therefore adc_sync must be set to sync_adc, to configure
# it's ADCLRC pin as input.
#
from machine import Pin, I2C
import wm8960
i2c = I2C(0)
wm=wm8960.WM8960(i2c, sample_rate=16_000,
adc_sync=wm8960.SYNC_ADC,
sysclk_source=wm8960.SYSCLK_PLL,
mclk_freq=24_000_000,
left_input=wm8960.INPUT_MIC1,
right_input=wm8960.INPUT_CLOSED)
Play with a Sparkfun WM8960 breakout board with Teensy in secondary mode (default)::
# The breakout board uses a fixed 24MHz MCLK. Therefore the internal
# PLL must be used as sysclk, which is the master audio clock.
# The Sparkfun board has the WS pins for RX and TX connected on the
# board. Therefore adc_sync must be set to sync_adc, to configure
# it's ADCLRC pin as input.
from machine import I2C
i2c=I2C(0)
import wm8960
wm=wm8960.WM8960(i2c, sample_rate=44_100,
adc_sync=wm8960.SYNC_ADC,
sysclk_source=wm8960.SYSCLK_PLL,
mclk_freq=24_000_000)
wm.set_volume(wm8960.MODULE_HEADPHONE, 100)