Steps to connect one external PDM microphone to QuickLogic Thing Plus board:
Ground connection
Power connection (+3.3V supplies check supply voltage level meeting connecting module requirement
Remove R28 (100Ω resistor)
Connect PDM CLK and PDM DATA signals; check IO level (> +3.0V IO only)
Keep connecting wires as short as possible
PDM microphone is configured as right channel microphone; the L/R signal or Channel signal is connected
to VDD
Check signal quality using scope
Double PDM Microphone
To support two external PDM microphones configuration, it is required to disable the connection of the on-board
PDM microphone.
QuickLogic Thing Plus supports external PDM microphone connection via expansion connector J8: PDM CLK (J8
pin 2) and PDM DATA (J8 pin 1).
Steps to connect two external PDM microphones to QuickLogic Thing Plus board:
Ground connection
Power connection (+3.3V supplies check supply voltage level meeting connecting module requirement
Remove R28 (100Ω resistor)
Connect PDM CLK and PDM DATA signals; check IO level (> +3.0V IO only)
Keep connecting wires as short as possible; avoid star connection scheme (see figure below)
Configure one PDM microphone as left channel and one PDM microphone as right channel
Check signal quality using scope
Board Dimensions
The board is 2.75"x2.10". While the board uses the Thing Plus footprint, length of the board is slightly longer than
other Thing Plus designs.
