Kinetis MicrocontrollersのトピックIt's PDM to PCM possible on KE04Z8?

It's PDM to PCM possible on KE04Z8?

Nicolas_Ottone — Mon, 26 Aug 2024 12:39:11 GMT

I need to connect a digital microphone and send samples serially to an external codec. My microphone, the MP34DT05, sends a PDM signal which I need to process to PCM and send the samples serially at a baud rate of +200k bauds.

Following the application note PDM to PCM in STM32 , I will use SPI to connect the microphone. I have noticed that the KE04 SDK doesn't have a driver for this type of microphone, while more powerful NXP microcontroller SDKs do.

My questions are:

Does the KE04 have the necessary resources to perform the PDM to PCM conversion?
Is the PDM driver software from more powerful microcontroller SDKs compatible with the KE04? (Obviously, I would need to adapt the pins).

Context:

Microcontroller: MKE04Z8VTG (Arm Cortex M0+, Clock up to 48Mhz, 8kb flash, 1kb sram)
Microphone: MP34DT05 (PDM)
Connection: Via SPI (CLK: Microphone Clock, MISO: Microphone DATA_OUT)
Goal: Convert PDM to PCM and send samples serially at +200k baud

I hope you can help me with this matter. Any advice or experience with PDM to PCM conversion on KE04 microcontrollers would be very helpful.

Thanks in advance for any help you can offer.

Re: It's PDM to PCM possible on KE04Z8?

xiangjun_rong — Tue, 27 Aug 2024 02:23:02 GMT

Hi,

Unfortunately, the KE04 does not have the interface to connect to the PDM device, furthermore, the KE04 does not have I2S module.

We have dedicated PDM module, which can convert PDM to PCM with internal digital filtering.

Pls refer to RM of LPC5411x, there is dedicated PDM module, the converted PCM can be put to I2S receiver data register directly.

Pls download UM10914.pdf from the link:

https://www.nxp.com/products/processors-and-microcontrollers/arm-microcontrollers/general-purpose-mcus/lpc54000-arm-cortex-m4-/low-power-microcontrollers-mcus-based-on-arm-cortex-m4-cores-with-optional-cortex-m0-plus-co-processor:LPC541XX

BTW, the latest MCXN family also has MICFIL module, which is alias of PDM, pls download the RM of MCXN family

https://www.nxp.com/products/processors-and-microcontrollers/arm-microcontrollers/general-purpose-mcus/mcx-arm-cortex-m/mcx-n-series-microcontrollers/mcx-n94x-54x-highly-integrated-multicore-mcus-with-on-chip-accelerators-intelligent-peripherals-and-advanced-security:MCX-N94X-N54X

The LPC646xx also has PDM.

This is the connection of PDM.

Hope it can help you

XiangJun Rong