What does "OSCERCLK in stop" mean?

[kenansun]

Hi,

I'm trying to use the low power mode on my Kinetis K60 MCU and I'm using PEx to do configurations. In CPU component, there is a property named "OSCERCLK in stop".

In the help of component, it says: "This property controls if external reference clock OSC0ERCLK remains enabled in STOP mode". But I still don't understand what this really does.

If I enable OSC0 in stop mode, does it mean all the clocks related to the OSC0 will keep running in the stop mode?

Many thanks!

Kenan

[BlackNight]

It means if you have that setting enabled, if you are in STOP mode, that this clock is still enabled (providing a clock).

If you want to see which bits and registers are affected by that setting, you could use the 'Configuration Registers' view, see Processor Expert Configuration Registers View | MCU on Eclipse

[kenansun]

Hi Erich,

Firstly thanks for your answer!

But if I keep this setting enabled, then the ARM core enters Deep Sleep Mode, doesn't it? I also read some ARM documents, it says,

• sleep mode stops the processor clock
• deep sleep mode stops the system clock and switches off the PLL and flash memory. (ref : ARM Information Center)

If my system clock is provided by the OSC0,

will it stop working or still work with "OSC0ERCLK in stop" enabled? What about an USB CDC Device using OSC1 source and with "OSC1ERCLK in stop" enabled?

Moreover, I find another option named "PLL module in Stop".

If I can choose to enable or not the PLL module in stop mode of Kinetis, is it in contradiction to the ARM documents?

Regards,

Kenan

[marek_neuzil]

Hello Kenan,

Please, see the deteiled description of power modes in a Kinetis reference manual - Chapter 7 -Power Management (e.g. http://cache.freescale.com/files/32bit/doc/ref_manual/K20P100M100SF2V2RM.pdf?fasp=1&WT_TYPE=Referenc... Manuals&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation&fileExt=.pdf). There is described how power modes are implemented on Kinetis derivatives.

The "OSC1ECLK in stop" mean the Stop mode described in the reference manual of the Kinetis derivative (it is not related to ARM terminology). For implementation of these power modes in PEx see the document https://community.freescale.com/docs/DOC-102163 (there is a table with all available modes).

Best Regards,

Marek Neuzil