RE: PDM interface

borg — Tue, 18 Feb 2020 14:53:52 GMT

Thanks a lot! I will try this and report back.

RE: PDM interface

Håkon Alseth — Tue, 18 Feb 2020 12:33:16 GMT

Hi,

If you add this to your prj.conf:

CONFIG_NRFX_PDM=y

Then you should be able to access the nrfx driver directly in your application, by including "#include <nrfx_pdm.h>" in your .c file, and interface it.

The "old" way of doing this, prior to tag v1.2.0, is described here:

https://devzone.nordicsemi.com/f/nordic-q-a/50656/using-pdm-mic-on-nrf9160dk/204715#204715

If you are using a fairly recent ncs, you should need to follow the very last step only, where you direct the interrupt in your main.c file:

ISR_DIRECT_DECLARE(pdm_isr_handler)
{
	nrfx_pdm_irq_handler();
	ISR_DIRECT_PM(); /* PM done after servicing interrupt for best latency
			  */

	return 1; /* We should check if scheduling decision should be made */
}

void main(void)
{
	IRQ_DIRECT_CONNECT(PDM_IRQn, 0,
			   pdm_isr_handler, 0);
	/* Rest of main */

Note: when compiling for non-secure, you need to set the peripheral as non-secure directly, as shown here: https://devzone.nordicsemi.com/f/nordic-q-a/68472/pdm-mic-on-nrf9160dk-and-spm/281880#281880

Kind regards,

Håkon