The Pulse Density Modulation (PDM)
module handles data streams from PDM microphones. The input data is decimated and
converted to PCM format with a configurable sinc filter. Data is made available in
various formats, sample rates and bit‑widths.
Features
- 2 PDM channels
- 1 PDM clock output and 2 PDM data
input pins
- Support for operation with single
mono, dual mono or stereo mic arrangements
- Selectable sampling rate
- Minimum 8kHz
- Common 16kHz
- Maximum 48kHz
- Configurable sinc‑filter order
- Configurable oversampling ratio
- Independent configurable clock
sources per data line
- Independent FIFO for each PDM
channel
- Support for FIFO data access in
8-bit, 16-bit and 32-bit modes
- Supported input formats
- Supported storage formats
- Right/left aligned
- Bipolar offset‑binary
- 2’s‑complement
- Support for operation with Host
DMA
- Availability of sample stamp
generator
- AGC accelerator for calculation
of signal average value, average power and peak values