Looking for documentation on "passive filter" function of GPIO's on KL03

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Looking for documentation on "passive filter" function of GPIO's on KL03

Jump to solution
1,158 Views
andrewsterianap
Contributor I

The reference manual says "Refer to the device data sheet for filter characteristics.", but the device data sheet does not have the word "passive" anywhere.

I've seen a similar question asked about the KL25 but the "correct answer" for that thread simply says "This filter is not the traditional filter. It is not high frequencty filter nor band filter. It can looks like a pulse counter. It will delete small width pulse. So it looks like a filter."

I'm really hoping for more information here, preferably with actual numbers!

Labels (1)
Tags (1)
0 Kudos
1 Solution
833 Views
jeremyzhou
NXP Employee
NXP Employee

Hi,

This filter (Passive filter) is not the traditional filter. It is not high frequency filter nor band filter. It 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.

Have a great day!

Ping

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

View solution in original post

0 Kudos
5 Replies
833 Views
PitOn
Contributor III

Hi.

majorization filter

example

input  port three samples  "101"
     two 1, one 0.   -> out 1 (dominates)

input  port 3 sample 001

     two 0, one 1.   -> out 0 (dominates)

Majorization - Wikipedia, the free encyclopedia

0 Kudos
833 Views
andrewsterianap
Contributor I

Thanks...is this documented anywhere in the NXP/Freescale docs? Does this imply there is a 3-clock-cycle delay in reading the GPIO pin?

0 Kudos
834 Views
jeremyzhou
NXP Employee
NXP Employee

Hi,

This filter (Passive filter) is not the traditional filter. It is not high frequency filter nor band filter. It 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.

Have a great day!

Ping

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

0 Kudos
833 Views
andrewsterianap
Contributor I

Thanks Ping. So it looks like there is just a 10-30 MHz low-pass filter on the pin. Do you know if there is any delay in reading the pin, recognizing edge-triggered interrupts, etc. due to this filtering?

0 Kudos
833 Views
jeremyzhou
NXP Employee
NXP Employee

Hi Andrew,

Sorry, I don't find any descriptions about the delay of the passive filter.

I think it doesn't matter.
Have a great day,
Ping

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

0 Kudos