Increasing CPU clock frequency for BL653

RE: Increasing CPU clock frequency for BL653

Jørgen Holmefjord — Thu, 29 Sep 2022 08:55:48 GMT

RE: Increasing CPU clock frequency for BL653

Ubaid_M — Thu, 29 Sep 2022 08:39:25 GMT

[quote userid="14926" url="~/f/nordic-q-a/92297/increasing-cpu-clock-frequency-for-bl653/388292"]This system clock is by default running off the 32.768 kHz LFCLK and an RTC instance[/quote]

Hello Jørgen Holmefjord,

Can you please let me know which RTC is being used herein..?

Thanks,

Ubaid

RE: Increasing CPU clock frequency for BL653

Jørgen Holmefjord — Wed, 28 Sep 2022 11:56:21 GMT

You can only change it to match the available clock sources.

The configs in this post should work on nRF52840, and thus likely also on nRF52833. Note that this is not low power and will keep the high-frequency clock running at all times.

RE: Increasing CPU clock frequency for BL653

Ubaid_M — Wed, 28 Sep 2022 09:32:18 GMT

[quote userid="14926" url="~/f/nordic-q-a/92297/increasing-cpu-clock-frequency-for-bl653/388292"]This will change the system clock of the Zephyr RTOS[/quote]

So this means increasing this will also increase timing for kernel services calculation, like threads, msgQ etc,.

How much maximum can i increase this for nrf52833..?

Thanks

RE: Increasing CPU clock frequency for BL653

Jørgen Holmefjord — Wed, 28 Sep 2022 09:03:15 GMT

[quote user="Ubaid_M"]So I am to understand that CPU frequency cannot be changed for nRF52833..?[/quote]

Yes, the CPU frequency is fixed and cannot be changed.

[quote user="Ubaid_M"]

So what is achieved by changing:

CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=32768

CONFIG_SYS_CLOCK_TICKS_PER_SEC=32768

..?

[/quote]

This will change the system clock of the Zephyr RTOS, which is used by the Kernel Timing services and Timers. This system clock is by default running off the 32.768 kHz LFCLK and an RTC instance. This is not related to the frequency of the CPU, and how fast the CPU can execute tasks.

RE: Increasing CPU clock frequency for BL653

Ubaid_M — Mon, 26 Sep 2022 12:34:42 GMT

Hello Jørgen Holmefjord,

[quote userid="14926" url="~/f/nordic-q-a/92297/increasing-cpu-clock-frequency-for-bl653/387887"]this is not configurable to higher of lower frequencies[/quote]

So I am to understand that CPU frequency cannot be changed for nRF52833..?

So what is achieved by changing:

CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=32768

CONFIG_SYS_CLOCK_TICKS_PER_SEC=32768

..?

RE: Increasing CPU clock frequency for BL653

Jørgen Holmefjord — Mon, 26 Sep 2022 11:40:01 GMT

Hi,

The CPU clock speed of nRF52833 is fixed at 64 MHz, this is not configurable to higher of lower frequencies.

Best regards,
Jørgen