LPC176x SPI and PDM microphone

[jeremybonhomme]

Hello,

I'm currently designing a board around LPC1765. I use a PDM microphone and I would like to interface it directly to the MCU. I saw few example with differents methods :

SPI in master mode : PDM in another 8-pin CPU | Words from Cheshire Engineering Corp. 

SPI in slave mode : https://community.nxp.com/message/766857?commentID=766857#comment-766857 

I2S interface (see attached doc)

First question : is it possible to interface PDM signal with LPC MCU ?

Second : is there any best solution between SPI master / slave and I2S ?

Thank you in advance

Regards

Jeremy BONHOMME

[jeremyzhou]

Hi Jeremy Bonhomme,
Thank you for your interest in NXP Semiconductor products and for the opportunity to serve you.
1) Is it possible to interface PDM signal with LPC MCU?
-- Definitely, it's available.
2) Is there any best solution between SPI master/slave and I2S?
-- It doesn't exist the best solution actually and it depends on which PDM microphone chip you use, for the LPC176x, it contains the SPI and I2S interface modules, so you can choose any PDM microphone chip which can support one of these interfaces.
Have a great day,
TIC

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[jeremybonhomme]

Hello,

Thank you for tour answer. We will used this microphone (SPK0838HT4H-B) and there is no protocol specification (it's the same familly as you used on your evaluation board). I will check free interfaces that I have on the MCU to choose how to connect thr microphone.