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# pdm_resources.h

struct pdm_rx_resources_t

  Collection of resources IDs required for PDM capture.

  This struct is a container for the IDs of the XCore hardware resources used by the mic array unit’s PdmRx component for capturing PDM data from a port.

  An object of this type will be used for initializing and starting the mic array unit.

  Public Members

  port_t p_mclk

    Resource ID of the 1-bit port on which the master audio clock signal is received.

    The master audio clock will be divided by a clock block to produce the PDM sample clock.

    This port will be configured as an input.

  port_t p_pdm_clk

    Resource ID of the 1-bit port through which the PDM sample clock is signaled.

    The PDM sample clock is used by the PDM microphones to trigger sample conversion.

    This port will be configured as an output.

  port_t p_pdm_mics

    Resource ID of the port on which PDM samples are received.

    In an SDR configuration, the number of microphone channels is the width of this port. In a DDR configuration, the number of microphone channels is twice the width of this port.

    This port will be configured as an input.

  clock_t clock_a

    Resource ID of the clock block used to derive the PDM clock from the master audio clock.

    In SDR configurations this is also the PDM data capture clock.

  clock_t clock_b

    Resource ID of the clock block used only in DDR configurations to trigger reads of the PDM data.

    If operating in an SDR configuration, `clock_b` is `0`. A value of `0` is what indicates an SDR configuration is being used.

PDM_RX_RESOURCES_SDR(P_MCLK, P_PDM_CLK, P_PDM_MICS, CLOCK_A)

  Construct a pdm_rx_resources_t for an SDR configuration.

  `pdm_rx_resources_t.clock_b` is initialized to `0`, indicating an SDR configuration.

  Parameters:

    - P_MCLK – Master audio clock port resource ID.

    - P_PDM_CLK – PDM sample clock port resource ID.

    - P_PDM_MICS – PDM microphone data port resource ID.

    - CLOCK_A – PDM clock and capture clock block resource ID.

PDM_RX_RESOURCES_DDR(P_MCLK, P_PDM_CLK, P_PDM_MICS, CLOCK_A, CLOCK_B)

  Construct a pdm_rx_resources_t for a DDR configuration.

  Parameters:

    - P_MCLK – Master audio clock port resource ID.

    - P_PDM_CLK – PDM sample clock port resource ID.

    - P_PDM_MICS – PDM microphone data port resource ID.

    - CLOCK_A – PDM clock clock block resource ID.

    - CLOCK_B – PDM capture clock block resource ID.