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CC3200-LAUNCHXL: How can I use SPI to acquire data from PDM MIC

Part Number: CC3200-LAUNCHXL
Other Parts Discussed in Thread: CC3200

Hi E2E,

We're working on a project in which we need use ultrasonic signal (stero-mode) acquired by PDM MICs and we want to use SPI to collect the data. I heard that in SPI prototype, the data are transmitted in frames (every 8-bit or 16-bit) and during the gap between every frame the data could be lost. Is there any possibility to collect the data continuously? Or is there any other solution? If it is, could you please send me a application note?  p.s. We want the data more ''continuous" but not "discrete".

Regards. 

  • Hi,

    Depending on the data buffering scheme used, it may be that data from the PDM microphone is lost. However, if the SPI clock rate is high enough this shouldn't be the case. This is since with SPI, the max clock rate of 20MHz should be much higher than the typical data rates needed for audio, so a single frame can be transferred much quicker than the actual time length of the frame, leaving sufficient overhead and preventing data loss.

    That being said, the CC3200 also has an I2S interface which is more suited for continuous streaming audio applications. I suggest taking a look at the wifi_audio_app example in the CCC3200 SDK for an example of how to use the I2S interface of the CC3200 for an audio streaming application.

    Let me know if you need more clarification on the SPI interface of the CC3200, or have further questions about interfacing the PDM microphones with the CC3200.

    Regards,

    Michael