What is the recommended way to use nRF52840 advanced PWM sequence and looping functions with nRF Connect SDK v2.9.0?

[Ken58]

Hi,

I am developing an application for an nRF52840 using nRF Connect SDK v2.9.0.  The application currently uses the Zephyr driver for simple PWM functions on several GPIOs. Now, I need to add PWM sequences and looping as supported by the SOC on other GPIOs. Correct me if I am wrong, but I don't think the Zephyr driver can support the Nordic PWM module in this way.

What is the best way to do this? Some questions that come to mind: Can the Zephyr PWM driver and the nrfx PWM driver live together in the same application? Must I chose one driver or the other? How does DeviceTree manage this? I'm sure I'll have more questions once the discussion is opened.

Thank you,

Ken

[Sigurd]

Hi!

The Zephyr driver API does not have the full functionality that is offered in nrfx pwm API.

So one option it to use nrfx directly. I would not recommend trying to mix and use both APIs.

https://github.com/zephyrproject-rtos/hal_nordic/blob/master/nrfx/samples/src/nrfx_pwm/common_mode/main.c

[Ken58]

Hi Sigurd,

I will check out the sample you mention.  For clarification, let me ask:

1. If I use the nrfx driver/API for PWM, can I continue to use the Zephyr GPIO driver/API?
2. What is the impact I will see in DeviceTree for PWM when using the nrfx driver/API?

Ken

[Ken58]

Hi again Sigurd,

As I look into how this can be done, is there an specific documentation section on using Zephyr with nrfx at the same time?  Is there a cookbook for this situation?  Is there a particular sample showing simultaneous use of Zephyr drivers for some devices and nrfx drivers/APIs for others?

[Ken58]

(Hi Sigurd,)**2

I may not have time to figure this out today, and in case you have a look at this on Monday:  I created a new application by picking the common_mode PWM sample from the library.  Without making any changes to the sample, when I attempt to "Add build configuration", it fails with the following output:

I would have thought this sample would have built without modification but it will not.  What do I need to do?  Is it documented somewhere?

Thanks again,

Ken

CCMakeError.log contents:

Compiling the C compiler identification source file "CMakeCCompilerId.c" failed.

Compiler: C:/ncs/toolchains/b620d30767/opt/zephyr-sdk/arm-zephyr-eabi/bin/arm-zephyr-eabi-gcc.exe

Build flags:

Id flags:  

The output was:

1

c:/ncs/toolchains/b620d30767/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.exe: c:/ncs/toolchains/b620d30767/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/lib\libc.a(lib_a-exit.o): in function `exit':

exit.c:(.text.exit+0x34): undefined reference to `_exit'

collect2.exe: error: ld returned 1 exit status

Compiling the CXX compiler identification source file "CMakeCXXCompilerId.cpp" failed.

Compiler: C:/ncs/toolchains/b620d30767/opt/zephyr-sdk/arm-zephyr-eabi/bin/arm-zephyr-eabi-gcc.exe

Build flags:

Id flags:  

The output was:

1

c:/ncs/toolchains/b620d30767/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/bin/ld.exe: c:/ncs/toolchains/b620d30767/opt/zephyr-sdk/arm-zephyr-eabi/bin/../lib/gcc/arm-zephyr-eabi/12.2.0/../../../../arm-zephyr-eabi/lib\libc.a(lib_a-exit.o): in function `exit':

exit.c:(.text.exit+0x34): undefined reference to `_exit'

collect2.exe: error: ld returned 1 exit status

[Ken58]

Hi Sigurd,

Do you have any response to why the sample application you mentioned will not build?

Thanks,

Ken