PDM can be configured with a single microphone (mono), or with two microphones.
When a single microphone is used, connect the microphone clock to CLK, and data to DIN.
The following figures show a single PDM microphone, wired as left.
Figure 2. Left wired microphone
The following figures show a single PDM microphone, wired as right.
Figure 3. Right wired microphone
Note that in a single microphone (mono) configuration, depending on the microphone’s
implementation, either the left or the right channel (sampled at falling or rising CLK edge
respectively) will contain reliable data.
If two microphones are used, one of them has to be set
as left, the other as right (L/R pin tied high or to GND on the respective microphone). It is
strongly recommended to use two microphones of exactly the same brand and type so that their
timings in left and right operation match.