Unused pin energy saving configuration

squareroot — Wed, 28 Nov 2018 14:53:52 GMT

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

Re: Unused pin energy saving configuration

Robin_Shen — Tue, 04 Dec 2018 03:13:02 GMT

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:

Best Regards,

Robin

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topic Unused pin energy saving configuration in Kinetis Microcontrollers

Unused pin energy saving configuration

Re: Unused pin energy saving configuration