Unused pin energy saving configuration

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

Unused pin energy saving configuration

801 Views
squareroot
Contributor I

Hi

My target is Kinetis E MKE06Z128VLH4 microcontroler and I am required to lower the power consumption to the minimum. What should I do with unused pins? In the AN4779 "EMC Design Tips for Kinetis E Family" note there is said to set unused pins as output low, but I am interested about other solution: isnt setting unused pins as input with pullup more energy saving?

Please let me know if the second solution isnt more energy saving.

Thanks

Darek

Tags (1)
0 Kudos
1 Reply

577 Views
Robin_Shen
NXP TechSupport
NXP TechSupport

Hi Darek,

Sorry for my late reply!

No. Please left these pins floating.
Initializing unused pins as output driving low during initialization is not required , but it will not cause a problem if the pins are configured this way.
The KE0x GPIO pins (except debug pins PTA4, PTA0, PTB4, and PTA5) are disabled after reset. This means that the input buffers and output buffers are in the high impedance state. The disabled input buffers will not exhibit any shoot-through currents in the input inverter with a mid-rail voltage on those pins.

About the second solution: unused pins as input with pullup
CASE3 system leakage occurs:

Fig3_internalpullupdowncell.JPG

Best Regards,

Robin

 

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

0 Kudos