What's the difference between passive filter and digtal filter of Kinetis K64?

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What's the difference between passive filter and digtal filter of Kinetis K64?

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wenxue
NXP Employee
NXP Employee

I found for Kinetis K64,PFE bit in PORTx_PCRn is used for passive filter and DFE in PORTx_DFER is userd for digtal filter. I don't know what's the difference between them  and which to select if used for hardware debounce?

Thanks!

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Hui_Ma
NXP TechSupport
NXP TechSupport

Hi,

Passive filter is a analog low pass filter (10 MHz to 30 MHz bandwidth).

Passive filter deals with analog signals and using to filter high frequency noise, the frequency more than 30MHz signal will be filtered.

Passive filter frequency is fixed and could not be modified.

Digital filter deals with digital input signals. Digital filter sets a filter gate (filter width in clock size), if input signal shorter than setting filter width, the input signal will be filtered.

The digital filter gate could be set by filter registers.

Wish it helps.
Have a great day,
Ma Hui

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Hui_Ma
NXP TechSupport
NXP TechSupport

Hi,

Passive filter is a analog low pass filter (10 MHz to 30 MHz bandwidth).

Passive filter deals with analog signals and using to filter high frequency noise, the frequency more than 30MHz signal will be filtered.

Passive filter frequency is fixed and could not be modified.

Digital filter deals with digital input signals. Digital filter sets a filter gate (filter width in clock size), if input signal shorter than setting filter width, the input signal will be filtered.

The digital filter gate could be set by filter registers.

Wish it helps.
Have a great day,
Ma Hui

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

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wenxue
NXP Employee
NXP Employee

Hi Ma Hui,

You say:

Passive filter is a analog low pass filter (10 MHz to 30 MHz bandwidth).

Passive filter deals with analog signals and using to filter high frequency noise, the frequency more than 30MHz signal will be filtered.”

I want to know where can I get this information?

Best Regards,

Wenxue

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Hui_Ma
NXP TechSupport
NXP TechSupport

Please get related feature description at Pin Control Register n (PORTx_PCRn) [PFE] bit description:

PFE.png

Wish it helps.
Have a great day,
Ma Hui

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

Regarding the screenshot you shared from the K60 Reference Manual... do the same specs apply to the K64? In the K64 Sub-Family Reference Manual, it does not specify the passive filter bandwidth, and I was unable to find any further info in the K64 Sub-Family Data Sheet.

PORTx_PCRn field descriptions:

pastedImage_1.png

k64‌ low pass filter‌ #port configuration

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wenxue
NXP Employee
NXP Employee

Hi Ma hui,

Would please to tell me what’s the chip of this RM?

I see for many chips’ RM, for example K22, it don’t show much information about passive filter. And datasheet also don’t have useful information.

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Hui_Ma
NXP TechSupport
NXP TechSupport

Hi,

Please check the K60_100MHz reference manual about related info.

Wish it helps.


Have a great day,
Ma Hui

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wenxue
NXP Employee
NXP Employee

OK Thanks.

Best Regards,

Wenxue

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wenxue
NXP Employee
NXP Employee

Hi Ma Hui,

Thanks! This is really helpful to me.

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