Beginners • RPI Zero 2W Max98357 and INMP441

Hi All,
I'm trying to use MAX98357 stereo amp with INMP441 mic so;

Hardware Setup
Raspberry Pi Zero 2W
INMP441 mic
MAX98357A I2S Amplifier (stereo setup)

Pin Configuration
Both devices share the same clock pins:
BCLK: GPIO18 - shared
LRCLK: GPIO19 - shared
Different data pins:
Microphone DOUT: GPIO20
MAX98357A DIN: GPIO21

Current /boot/config.txt
dtparam=i2s=on
dtoverlay=googlevoicehat-soundcard
dtoverlay=max98357a

Problem
Currently, only the last dtoverlay in config.txt works. If max98357a is last, I can only use the amplifier. If googlevoicehat-soundcard is last, I can only use the microphone.
The MAX98357A works perfectly in stereo mode when used alone, but I cannot integrate the I2S microphone into this system.

My questions are:
Is it possible to use both overlays simultaneously since they share clock pins but use different data pins?
Should I create a custom device tree overlay that combines both functionalities?
Are there any existing overlays that support simultaneous I2S input and output?
What's the recommended approach for I2S microphone + I2S amplifier setup?

BR

Statistics: Posted by persoentif — Tue Jul 08, 2025 1:55 pm

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