Interfacing the PDM Mic in nrf52832 using NCS3.0

[Tarunraj Singh]

Hello NRF Community, I am trying to interface the Adafruit PDM MEMS Microphone (Link: https://www.adafruit.com/product/3492) with my nrf52832dk. However, it fails every time. My ncs version is 3.0.0. I am providing my code for the reference. 

Everytime I see this log:-

FAILED: modules/hal_nordic/modules/hal_nordic/nrfx/CMakeFiles/modules__hal_nordic__nrfx.dir/C_/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c.obj 
C:\ncs\toolchains\0b393f9e1b\opt\zephyr-sdk\arm-zephyr-eabi\bin\arm-zephyr-eabi-gcc.exe -DCONFIG_GPIO_AS_PINRESET -DKERNEL -DK_HEAP_MEM_POOL_SIZE=0 -DNRF52832_XXAA -DPICOLIBC_LONG_LONG_PRINTF_SCANF -DUSE_PARTITION_MANAGER=1 -D__LINUX_ERRNO_EXTENSIONS__ -D__PROGRAM_START -D__ZEPHYR__=1 -IC:/ncs/v3.0.0/pdmMicNRF/build/pdmMicNRF/zephyr/include/generated/zephyr -IC:/ncs/v3.0.0/zephyr/include -IC:/ncs/v3.0.0/pdmMicNRF/build/pdmMicNRF/zephyr/include/generated -IC:/ncs/v3.0.0/zephyr/soc/nordic -IC:/ncs/v3.0.0/zephyr/soc/nordic/nrf52/. -IC:/ncs/v3.0.0/zephyr/soc/nordic/common/. -IC:/ncs/v3.0.0/nrf/include -IC:/ncs/v3.0.0/nrf/tests/include -IC:/ncs/v3.0.0/modules/hal/cmsis/CMSIS/Core/Include -IC:/ncs/v3.0.0/zephyr/modules/cmsis/. -IC:/ncs/v3.0.0/nrf/modules/hal_nordic/. -IC:/ncs/v3.0.0/modules/hal/nordic/nrfx -IC:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/include -IC:/ncs/v3.0.0/modules/hal/nordic/nrfx/mdk -IC:/ncs/v3.0.0/zephyr/modules/hal_nordic/nrfx/. -IC:/ncs/v3.0.0/modules/debug/segger/SEGGER -IC:/ncs/v3.0.0/modules/debug/segger/Config -isystem C:/ncs/v3.0.0/zephyr/lib/libc/common/include -fno-strict-aliasing -Os -imacros C:/ncs/v3.0.0/pdmMicNRF/build/pdmMicNRF/zephyr/include/generated/zephyr/autoconf.h -fno-printf-return-value -fno-common -g -gdwarf-4 -fdiagnostics-color=always -mcpu=cortex-m4 -mthumb -mabi=aapcs -mfp16-format=ieee -mtp=soft --sysroot=C:/ncs/toolchains/0b393f9e1b/opt/zephyr-sdk/arm-zephyr-eabi/arm-zephyr-eabi -imacros C:/ncs/v3.0.0/zephyr/include/zephyr/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wdouble-promotion -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined -Wno-unused-but-set-variable -Werror=implicit-int -fno-pic -fno-pie -fno-asynchronous-unwind-tables -ftls-model=local-exec -fno-reorder-functions --param=min-pagesize=0 -fno-defer-pop -fmacro-prefix-map=C:/ncs/v3.0.0/pdmMicNRF=CMAKE_SOURCE_DIR -fmacro-prefix-map=C:/ncs/v3.0.0/zephyr=ZEPHYR_BASE -fmacro-prefix-map=C:/ncs/v3.0.0=WEST_TOPDIR -ffunction-sections -fdata-sections -specs=picolibc.specs -std=c99 -MD -MT modules/hal_nordic/modules/hal_nordic/nrfx/CMakeFiles/modules__hal_nordic__nrfx.dir/C_/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c.obj -MF modules\hal_nordic\modules\hal_nordic\nrfx\CMakeFiles\modules__hal_nordic__nrfx.dir\C_\ncs\v3.0.0\modules\hal\nordic\nrfx\drivers\src\nrfx_pdm.c.obj.d -o modules/hal_nordic/modules/hal_nordic/nrfx/CMakeFiles/modules__hal_nordic__nrfx.dir/C_/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c.obj -c C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:68:5: error: unknown type name 'nrfx_nrfx_pdm_buffer_set_t'
   68 |     nrfx_nrfx_pdm_buffer_set_t  event_handler;    ///< Event handler function pointer.
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c: In function 'pdm_init':
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:177:25: warning: assignment to 'int' from 'nrfx_pdm_event_handler_t' {aka 'void (*)(const nrfx_pdm_evt_t *)'} makes integer from pointer without a cast [-Wint-conversion]
  177 |     p_cb->event_handler = event_handler;
      |                         ^
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c: In function 'irq_handler':
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:640:13: error: called object is not a function or function pointer
  640 |             p_cb->event_handler(&evt);
      |             ^~~~
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:654:17: error: called object is not a function or function pointer
  654 |                 p_cb->event_handler(&evt);
      |                 ^~~~
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:677:13: error: called object is not a function or function pointer
  677 |             p_cb->event_handler(&evt);
      |             ^~~~
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:685:13: error: called object is not a function or function pointer
  685 |             p_cb->event_handler(&evt);
      |             ^~~~
C:/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_pdm.c:699:9: error: called object is not a function or function pointer
  699 |         p_cb->event_handler(&evt);
      |         ^~~~
[81/122] Building C object modules/hal_nordic/modules/hal_nordic/nrfx/CMakeFiles/modules__hal_nordic__nrfx.dir/C_/ncs/v3.0.0/modules/hal/nordic/nrfx/drivers/src/nrfx_gpiote.c.obj
[82/122] Building C object zephyr/kernel/CMakeFiles/kernel.dir/busy_wait.c.obj
[83/122] Building C object zephyr/kernel/CMakeFiles/kernel.dir/errno.c.obj
[84/122] Linking C static library zephyr\drivers\serial\libdrivers__serial.a
[85/122] Linking C static library modules\segger\libmodules__segger.a
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: 'C:\ncs\toolchains\0b393f9e1b\opt\bin\cmake.EXE' --build C:/ncs/v3.0.0/pdmMicNRF/build/pdmMicNRF

 *  The terminal process terminated with exit code: 1. 
 *  Terminal will be reused by tasks, press any key to close it. 

pdmMicNRF.zip

Can somebody please help me with my code or provide me an example code on how to interface and get the readings of the PDM mic in nrf52832dk. 

Thanks in advance!

[Benjamin]

Hi Tarunraj,

Have you looked at this sample?

This simple app shows how to use the Audio DMIC API and helps with driver development by doing two PDM transfers with different channel setups, without processing the audio.

Best regards,
Benjamin

[Tarunraj Singh]

Hi Benjamin, 
Thanks for the response

I have tried the sample example. However, I found out that it is only working with nrf52840dk, not with nrf52832dk. 
I tried to build the configurations on both the controller boards, succeeding with nrf52840dk, however failing with nrf52840dk each time. 

Is it really the problem of board or I am having some misconception? 

[Benjamin]

Hi,
The build fails for the nRF52832 because a required overlay file is missing. To fix this, create a copy of dmic/boards/nrf52840dk_nrf52840.overlay and rename it to dmic/boards/nrf52dk_nrf52832.overlay. I don’t see any differences needed for this overlay, so you can copy it as-is. The build should succeed afterward.

Best regards,
Benjamin

[Tarunraj Singh]

Thank You So Much Benjamin!!
It worked!!