docs/psoc6/quickref.rst: Would be supported PDM API's.

Signed-off-by: NikhitaR-IFX <Nikhita.Rajasekhar@infineon.com>

docs/psoc6/quickref.rst

@@ -579,6 +579,101 @@ Constructor
  audio_in = I2S(0, sck="P5_4", ws="P5_5", sd="P5_6", mode=I2S.RX, bits=16, format=I2S.STEREO, rate=22050, ibuf=20000) # create I2S object
  num_read = audio_in.readinto(buf)# fill buffer with audio samples from I2S device
 
+PDM_PCM bus
+------------
+class PDM -- PDM/PCM protocol
+========================================
+
+PDM/PCM is a asynchronous operation serial used to connect digital audio devices.
+At the physical level, a bus consists of 2 lines: SCK, SD.
+
+PDM objects can be created and initialized using::
+
+ from machine import PDM_PCM
+ from machine import Pin
+
+ sck_pin = Pin('P10_4') # Serial clock output
+ data_pin = Pin('P10_5') # Serial data output
+
+ pdm_pcm_rx = PDM_PCM(2,
+ sck=sck_pin, data=data_pin,
+ mode=PDM_PCM.RX,
+ bits=16,
+ format=PDM_PCM.MONO,
+ rate=44100,
+ ibuf=20000)
+
+2 modes of operation are supported:
+ - blocking
+ - non-blocking
+
+
+Constructor
+-----------
+
+.. class:: PDM_PCM(id, *, sck, data, mode, bits, format, rate, ibuf)
+
+ Construct an I2S object of the given id:
+
+ - ``id`` identifies a particular I2S bus; it is board and port specific
+
+ Keyword-only parameters that are supported on all ports:
+
+ - ``sck`` is a pin object for the serial clock line
+ - ``data`` is a pin object for the data line
+ - ``mode`` only receive is supported in psoc6
+ - ``rate`` specifies audio sampling rate (Hz)
+ - ``decimation_rate`` is PDM decimation rate
+ - ``format`` specifies channel format, STEREO, MONO_LEFT or MONO_RIGHT
+ - ``word_length`` specifies word length (bits), 16, 18, 20, 24
+ - ``left_gain`` is PGA in 0.5 dB increment
+ - ``right_gain`` is PGA in 0.5 dB increment
+ - ``ibuf`` specifies internal buffer length (bytes)
+
+Methods
+-------
+
+.. method:: PDM_PCM.init(sck, ...)
+
+.. method:: PDM_PCM.deinit()
+
+.. method:: PDM_PCM.readinto(buf)
+
+.. method:: PDM_PCM.irq(handler)
+
+.. method:: PDM_PCM.gain(gain_left, gain_right)
+
+.. method:: PDM_PCM.start()
+
+.. method:: PDM_PCM.stop()
+
+Constants
+---------
+
+.. data:: PDM.RX
+
+ for setting mode to receive
+
+.. data:: PDM.STEREO
+
+ for initialising the PDM_PCM ``format`` to stereo
+
+.. data:: PDM.MONO_LEFT
+
+ for initialising the PDM_PCM ``format`` to mono-left
+
+.. data:: PDM.MONO_RIGHT
+
+ for initialising the PDM_PCM ``format`` to mono-right
+
+.. data:: PDM.MONO_RIGHT
+
+ for initialising the PDM_PCM ``format`` to mono-right
+
+.. data:: PDM.MONO_RIGHT
+
+ for initialising the PDM_PCM ``format`` to mono-right
+
 
 UART
 ----