What to do with unused pins?

[Nobis1]

Good day,
I used the MKM34Z256VLQ7 in my application.
In my circuit design I don't use many pins.
Almost all of them are "Disabled" as "DEAFULT" value.
I don't know exactly what to do with these pins.
Can they float, do they have to go to GND or VDD.
Does this have to happen through a resistoro or capacitor.
I could find in the "Kinetis KM34 Sub-Family Reference
Manual" no correct answer for this.

Can someone give me a hint or help me with this?

[john_suchyta · Accepted solution]

Hi Nobis1,

The official NXP recommendation for unused Kinetis GPIO pins is to leave them disconnected from the board (no bias) and in their default state. This means that the digital GPIO pin is in its Disabled state (input and output buffers disabled) or configured as an analog channel. Unused analog-only pins should be left floating. Here is a link to one of the discussions for reference:

https://community.nxp.com/t5/Wireless-Connectivity-Knowledge/Configuration-for-Unused-Pins-GPIOs-on-...

Some of our datasheets contain a section regarding termination of unused functional pins but I did not find it in the Kinetis M datasheets. Unused GPIO information is not available in Kinetis reference manuals.

Regards,

John Suchyta

[myke_predko]

@Nobis1 

I would recommend making any unused pins inputs (digital or analog) and tie them to GND through a zero Ohm resistor.  

The zero Ohm resistor provides you with pads so if the need arises, the pin can be used for testing out new peripherals.  

[972794]

We are using MIMXRT1176DVMAA NXP processor some of the pins are not using in our application (Ex. MIPI and USB interface),so those pins shall we left the pins are floating or tie to GND with resistor for signal and power pins.