Is it possible to enter low power mode without modifying clocks?

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Is it possible to enter low power mode without modifying clocks?

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mitterha
Senior Contributor I

Hello,

according to AN12085 each low power mode (including system idle) includes changing the clock frequencies

pastedImage_1.png

  1. Is there a way to keep clock settings with their normal "run" frequency (e.g. SPI is still clocked with 66 MHz, FlexSPI 132 MHz) and just put the core in a wait for interrupt / powerdown state?
  2. The application note also states that changing the flexspi root clock is dangerous if you use XIP (we do)
    pastedImage_2.png
    so should we never use any low power mode or should we just put the code which switches to low power mode into internal RAM?

Kind regards,

Stefan

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1 Solution
653 Views
jeremyzhou
NXP Employee
NXP Employee

Hi  Stefan Mitterhauser,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
1) Is there a way to keep clock settings with their normal "run" frequency (e.g. SPI is still clocked with 66 MHz, FlexSPI 132 MHz) and just put the core in a wait for interrupt / power-down state?
-- No, I'm afraid not.
2) so should we never use any low power mode or should we just put the code which switches to low power mode into internal RAM?
-- The above statement is used to help the developers to design more robust code to enter any low power mode, as it says, it'd better remap the clock change code or function to the On-chip RAM to run.

Have a great day,
TIC

 

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654 Views
jeremyzhou
NXP Employee
NXP Employee

Hi  Stefan Mitterhauser,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
1) Is there a way to keep clock settings with their normal "run" frequency (e.g. SPI is still clocked with 66 MHz, FlexSPI 132 MHz) and just put the core in a wait for interrupt / power-down state?
-- No, I'm afraid not.
2) so should we never use any low power mode or should we just put the code which switches to low power mode into internal RAM?
-- The above statement is used to help the developers to design more robust code to enter any low power mode, as it says, it'd better remap the clock change code or function to the On-chip RAM to run.

Have a great day,
TIC

 

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!

 

- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

653 Views
mitterha
Senior Contributor I

Thank you for your answer jeremyzhou‌!

Kind regards,

Stefan

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