Low power is not supported with enabled cache, See Appnote: 1234

[danielchai]

Hi,

I am tring to use the MQX4.0.2. But after setting MQX_ENABLE_LOW_POWER TO 1 on user_config.h, when compile BSP, it gives me this error:

Low power is not supported with enabled cache, See Appnote: 1234.

But I did not find where is Appnote: 1234.

Any ideas about this? Or how can I disable the cache?

Thanks.

[brianpaterson]

Daniel,

You ever get an answer to this? Somehow, not surprised as the 4.0.2.2 update is still leaving this hanging out in the wind.

I have the K60F120M with the 1M0 memory and ran straight into this error.

I set, since I really need to, the MQX_ENABLE_LOW_POWER to 1 in the config

I also set, since the bsp is giving errors like crazy, the following in the config:

MQX_DISABLE_CACHE          1

Hey, we'll see if this works.

Let me know if you find anything.

Brian

[dereksnell]

Hi Brian,

Why do you say "4.0.2.2 update is still leaving this hanging out in the wind”?  Earlier releases of MQX used the preprocessor error below in \mqx\source\psp\cortex_m\kinetis.h to prevent users from having the cache enabled when entering low-power mode, to avoid issues with erratum e7166.  But in the latest MQX v4.0.2.2, this has been removed.  And the v4.0.2.1/2 release notes show the workaround was implemented:

ENGR00270143

§ Software workaround for Errata e7166, which is relevant for Mask 3N96B silicon.

§ Affected BSPs: TWR-K60F120M and TWR-K70F120M

#if MQX_ENABLE_LOW_POWER && (PSP_HAS_CODE_CACHE || PSP_HAS_DATA_CACHE)

#error Low power is not supported with enabled cache, See Appnote: 1234

#endif

[brianpaterson]

Derek,

I still have it in the build - Freescale_MQX_4_0\lib\twrk60f120m.uv4/release/psp/kinetis.h

Lines 162 through 164:

#if MQX_ENABLE_LOW_POWER && (PSP_HAS_CODE_CACHE || PSP_HAS_DATA_CACHE)

#error Low power is not supported with enabled cache, See Appnote: 1234

#endif

This is 4.0.2.2 updated. Sorry.

I plan on installing a clean 4.0.2 install and looking at the 4.0.2.1 and 4.0.2.2 updates to see the differences.

Now, is it possible that my install is messed up? Sure!

It's also been heavily beaten up.

Also, while I have you on the telephone (OK, I know...) my scatter file seems to go nuts every once in a while with the vectors.o FIRST/LAST error. Not sure why... Any ideas? Any relation to using low power / sleep routines?

Thanks!

Brian

[richardzieminsk]

Can you confirm Low Power Mode(s) are supported now with cache enabled?  I see no mention either way in the app. note (AN4447) you listed.  Would that mean I should comment out/ignore the warming(s) int the BSP? Specifically kinetis.h.

Thanks,

Rich

[susansu]

Hi,

About how to use low power mode, you could refer to AN4447 - Freescale MQX Low-Power Management

http://cache.freescale.com/files/32bit/doc/app_note/AN4447.pdf?fpsp=1&WT_TYPE=Application Notes&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation

[BielikM]

Hi.

As i know this issue has been fixed(or workarounded) in 4.0.2.2 release.

Regards