Core / Peripheral States after wakeup from low power mode

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Core / Peripheral States after wakeup from low power mode

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simonwyss
Contributor III

Which peripherals are powered after different low power states?

I found some information in the application note AN11611 and the user-manual UM10850 but I don't know if the RTC is always started after reset from sleep, deep-sleep or power-down mode?
If I use only the IRC as clock, I think the IRC has to start after the sleep, deep-sleep or power-down mode. Because ther is no other clock available.

However, when I switch to the RTC (32kHz) bevor going to sleep, deep-sleep or power-down, what happens on wakeup?
Is the IRC automatically started? Is the main-clock-source automatically switched to the IRC clock?
If not, I would have to switch the main-clock-source manually to IRC (with the 32kHz Clock, using 32us for each CPU cycle)



Thank you in advance for your help!

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There seems to be an error in the AN11611 on page 5: The IRC is shutdown in Deep-Sleep according to the user-manual:

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1 Solution
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jeremyzhou
NXP Employee
NXP Employee

Hi Simon Wyss,

1) Which is the main-clock-source after wakeup? 

- RTC (32kHz)

- IRC (12MHz)

Depend on the previous option configured, the MCU will resume execute with the original clock source after wake up.

Please you can have a try.
Have a great day,
TIC

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3 Replies
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jeremyzhou
NXP Employee
NXP Employee

Hi Simon Wyss ,

1) when I switch to the RTC (32kHz) bevor going to sleep, deep-sleep or power-down, what happens on wakeup?

    I think the MCU will resume execute after wake up events happen.
Have a great day,
TIC

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

974 Views
simonwyss
Contributor III

Hi jeremyzhou 
Thank you for your reply!

1) Which is the main-clock-source after wakeup? 

- RTC (32kHz)

- IRC (12MHz)

2) Is the IRC always powered up after wakeup?

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975 Views
jeremyzhou
NXP Employee
NXP Employee

Hi Simon Wyss,

1) Which is the main-clock-source after wakeup? 

- RTC (32kHz)

- IRC (12MHz)

Depend on the previous option configured, the MCU will resume execute with the original clock source after wake up.

Please you can have a try.
Have a great day,
TIC

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