7.6.6.2 Clocks and Output Sampling Rate

The clock sent to the PDM microphone is GCLK/16.

The controller continuously decimates the incoming streams. The output sampling rate depends on PDMC_MR.OSR.

Table 7-14. Conversion Rates
PDMC_MR.SINC_OSR	PDMC_MR.OSR	Audio Filter	OSR⁽¹⁾	Description and Oversampling Ratio (OSR⁽¹⁾)
0	0	Yes	–	Forbidden
	1	Yes	64	Audio filtering with OSR⁽¹⁾ = 2^{(PDMC_MR.OSR+5)}
	2	Yes	128
	3	Yes	256
> 0	–	No	OSR⁽¹⁾ = 2^{(PDMC_MR.SINC_OSR+2)}	The maximum SINC_OSR corresponds to an OSR⁽¹⁾ of 256.

Note:

The OSR is defined by the ratio between the clock frequency of the PDMC (i.e., GCLK/16) and the output sampling rate after filtering and decimation.