PDM clock not generated

[viktorkesler]

I haven't connected a PDM Mic yet (waiting for it to arrive) but have noticed that the Serial output example does not generate a clock on GPIO3 but the USB example does.

I'm a beginner with RP2040 so have no hope of finding the difference in the two examples, I just need one example to work with RP2040 and a PDM mic.

The USB example causes Audacity to hang when the Pico is attached (without a PDM mic).

[viktorkesler]

Just to add that I've found that if I move the pdm_init, pdm_microphone_set_samples and pdm_start functions BEFORE the serial port initialisation i.e. before this bit:

stdio_init_all(); while (!tud_cdc_connected()) { tight_loop_contents(); } printf("hello PDM microphone\n");

I do get a clock on GPIO3 and (since I still haven't got a MIC) connecting GPIO2 (DATA) to 3V3 gives a 0 output and leaving it open or connecting to GND gives a -512 output.

[sandeepmistry]

Hi @viktorkesler,

tud_cdc_connected() wait for the USB serial port to be open, so in the original example code the microphone will be initialized after this.

[viktorkesler]

Thanks for your reply but I'm not quite sure what you are saying.

I realise the microphone is initialised after

tud_cdc_connected()

in the original code.

But that doesn't generate a clock on GPIO3. Hence my previous message.

[stale[bot]]

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