Application core clock frequency configuration

[MartaOp]

Hi, 

I tried to configure application core frequency from 128 MHz to 64 Mhz using thee function:

nrfx_clock_divider_set(NRF_CLOCK_DOMAIN_HFCLK,NRF_CLOCK_HFCLK_DIV_2);

but I've got an error:  "This code is not supposed to be compiled when neither POWER nor CLOCK is enabled."

 

I've checked on the forum and I found this thread: 

https://devzone.nordicsemi.com/f/nordic-q-a/62533/using-16mhz-spim-on-nrf5340-pdk

The author mentioned that he set the clock configuration directly - How can I do that without throwing the error?

Thanks, 

Marta

[JONATHAN LL]

Hi Marta,

I think the NRFX_CLOCK_ENABLED needs to be set to use the function.
Try setting this CONFIG_COMPILER_OPT="-DNRFX_CLOCK_ENABLED" in the prj.conf.

Regards,
Jonathan

[MartaOp]

Hi Jonathan, 

I've checked it and after changing only this one line I've got:

 undefined reference to `nrfx_clock_divider_set'

I attached the  #include <nrfx_clock.h> library but it's not finding it. 

Is there any other way to set it up?

Thanks,

Marta

[JONATHAN LL]

Hi, 
Check to se if this fixes the problem:

CONFIG_COMPILER_OPT="-DNRFX_CLOCK_ENABLED=1"

and if there are some problems down the line with non-secure/secure then this might help:

CONFIG_COMPILER_OPT="-DNRF_CLOCK=NRF_CLOCK_NS -DNRFX_CLOCK_ENABLED=1"

Regards,
Jonathan

[MartaOp]

Hi Jonathan,

Unfortunately, non of those configuration works. Just to clarify:

- I'm using secure build so I've changed the CONFIG_COMPILER_OPT="-DNRF_CLOCK=NRF_CLOCK_NS -DNRFX_CLOCK_ENABLED=1" to CONFIG_COMPILER_OPT="-DNRF_CLOCK=NRF_CLOCK_S -DNRFX_CLOCK_ENABLED=1" but neither works

- Should nrfx_clock_divider_set(NRF_CLOCK_DOMAIN_HFCLK,NRF_CLOCK_HFCLK_DIV_2); be the first function in main or maybe it should be somewhere else?

I still get "undefine reference" so I tried code:

NRF_CLOCK_NS.HFCLKCTRL = CLOCK_HFCLKCTRL_HCLK_Div1 << CLOCK_HFCLKCTRL_HCLK_Pos;

There is some parenthesis missing: "expected identifier or '(' before 'NRF_CLOCK_Type'
1> ../src/main.c:30:1: note: in expansion of macro 'NRF_CLOCK_NS'"

 

Thanks, 

Marta

[JONATHAN LL]

Hi

Have you seen this post? https://devzone.nordicsemi.com/f/nordic-q-a/59697/nrf5340---how-to-change-clock-freq-of-app-core-on-the-fly

For reference hare is a link to the Clock Changing frequency errata referenced in the mentioned post, link.

I will try to reproduce the scenario myself or se if any colleagues have had a similar issue and get back to you.

Regards,
Jonathan