16bit voice input from RT1170-EVK PDM microphones

[yf2]

Dear support,

Would you please teach how to efficiently get 16bit voice wave data from PDM microphones on RT1170-EVK device?

the MCUExpresso SDK defines data width for 24bit and 32bit when FSL_FEATURE_PDM_FIFO_WIDTH is set as (4), this is the case in my MIMXRT1176_cm7_features.h.

How can we do 16bit data capture via PDM driver on RT1170-EVK board? Do we have to capture in 24 or 32bit then convert to 16bit manually?

The old ticket1 and ticket2 will be closed to avoid duplications.

Regards,

yf2

[kerryzhou]

Hi @yf2 ,

   Please help to check one point, how many bit of your external mic? 16bit? signed?

   Please give me reply, then I will check with our expert again, thanks.

Best Regards,

Kerry

[yf2]

Kerry,

We cosulted contact of PDM microphone vendor and they said it is up to the PDM receiver side to decide the audio output data width. Some receivers may output 24bit, some may output 16bit.

So please kindly check with RT117x team and let me know what I can do with the microphone vendor.

Regards,

yf2

[kerryzhou]

Hi @yf2 ,

  I already get our internal expert reply: RT1170 PDM is 24 bit, but it also supports 16bit, when you want to use the 16 bit, just read the higher 16 bit in the get 24 bit data.

Wish it helps you!

Best Regards,

Kerry

[kerryzhou · Accepted solution]

Hi @yf2 ,

  From the RT1170 RM, it is 24 bit:

Anyway, I will help you double check with our internal side, whether it can support 16 bit or not, then I will give you updated information.

Best Regards,

kerry