Sleep Mode K60 MK60DN512VLQ10

[sivaveluppillai]

I have question on the K60 micro sleep! 
We are running our K60 micro MK60DN512VLQ10 from a system oscillator 16MHz clock (Core clock is 96MHz) and we also have the external RTC oscillator 32.768kHz.
We have a low power requirement when battery powered.
In this low power mode, we sleep for 250mS and wake up and check for reason to wake and sleep again.
During this 250mS sleep the only thing needed to work is wake up from pin change/pin interrupt.
Requirements:
So looking at the power mode options, VLPS is the most appropriate mode although we are happy to consider other power modes.
I am also thinking we could use the 1kH LPO for the sleep clock but not sure it can do 250mS. This can be utilised with the internal wdog?
We don’t need super accuracy but the 1kHz clock has +/-10% accuracy and it is pretty bad. So I am wondering whether we could calibrate the 1kHz. May be another way?
Any sample code/app note for this?
I have the followings:
AN4503 Power Management for Kinetis MCUs

AN4470 Using Low Power modes on Kinetis family

K60 Sub-Family Reference Manual

Any other suggestions can also be considered?

Previously we considered the VLPR, the issue is this mode still keeps the core frequency running and changing the clock to 32kHz may be a solution but has no benefit!
We are using Code Warrior IDE for the development!

[Omar_Anguiano]

Hello SIVA VELUPPILLAI

According to your requirements, the VLPS is a good choice since the wake up from pin interrupt is available.

Just to clarify, what do you mean for "The LPO can do 250ms"? It's important to consider the transition time between the power modes, for the case of VLPS to Run the time is 2-4us + 12 clock cycles.

The LPO can be used with the watchdog and its available in VLPS.

Unfortunately, the LPO can't be calibrated, I apologize for the inconvenience this may cause you.

Let me know if this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar

[sivaveluppillai]

Thanks Omar,

We have used PE to generate the code, is it possible to use the PE to generate the two transition modes, full run and sleep settings? 

Otherwise please provide some sample code for the sleep mode timer 250mS, we can use either LPO or another timer. 

[Omar_Anguiano]

Hello SIVA VELUPPILLAI

You can refer to this post about Operation modes in Processor Expert https://community.nxp.com/docs/DOC-102163 

In the SDK you will find examples about power management, in the examples, the wakeup is made from a GPIO or from the LPTMR https://mcuxpresso.nxp.com/en/welcome

Wish this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar

[sivaveluppillai]

It is not very clear in your instructions how to set the PE for the low power mode!
You have provided the PE example for the Kinetis L series. Our processor is K60 and it is not the L version as this may be the reason I couldn’t see the some of the options.
I enabled the low power mode as per the PE example you have provided but in the “Sleep operation mode” Low Power mode STOP, PSTOP1, PSTOP2 cannot be found.
Also regarding the clock settings, are you suggesting to add an additional “Clock configuration” for the VLPS? I can add additional clock configuration by increasing this from 1 to 2, but it won’t let me set the 32kHz clock as the main clock.

In our case we run everything from the 16MHz/ 32.768 kHz external clocks and we need to sleep with 32.768kHz during a mains fail condition.
Is it possible to make the PE to generate code fort the above condition? If so please provide some instructions. 

BTW: Have you actually developed anything using CodeWarrior with PE? If not could you please reassign another person with this expertise? Thank you!

[Omar_Anguiano]

Hello SIVA VELUPPILLAI

I've been doing some configuration with PE to enable the VLPS  but unfortunately, this option is not available in CodeWarrior. This need to be written, I suggest you take as reference the SDK power management examples.

If you want to use the external 32KHz clock, you may want to use the LPTMR clock and attach the external 32Khz clock as source. The LPTMR can set an interrupt in order to wake the device.

If you have more questions do not hesitate to ask me.

Best regards,

Omar