Termination of unused pins of 56F83600 Microcontroller

[MrPMTX]

I am using an MC56F83689 in my application. Many pins are not used in our design.

As it is stated in the Datasheet, we want tie them to an appropriate voltage level to get a more reliable operation.

Is there any default recommendation for every unused pin of this device?

Can I connect every unused GPIO directly to ground?

As I remember VDD_USB to VDD and VSS_USB to VSS, USB_DP & USB_DM n.c. is recommended if USB is not used, correct?

What about GPIOC1/XTAL if external Clock is used at CLKIN? Shall I configure it as GPIO and tie it to ground?

The complete list of unused pins is attached

[Celeste_Liu · Accepted solution]

Hello @MrPMTX ,

Thanks for your post.

Can I connect every unused GPIO directly to ground?

-> Yes, you can directly connect all the unused GPIOs to ground.

As I remember VDD_USB to VDD and VSS_USB to VSS, USB_DP & USB_DM n.c. is recommended if USB is not used, correct?

-> You can connect VSS_USB to VSS and leave the USB_DP and USB_DM pins floating. There are two options for handling VDD_USB: one is to connect it to VDD; the other is to tie it to ground through a 10 kΩ resistor.

What about GPIOC1/XTAL if external Clock is used at CLKIN? Shall I configure it as GPIO and tie it to ground?

->Yes, you can configure GPIOC1/XTAL as a GPIO and then tie it to ground.

Hope it can help you.

BRs,

Celeste

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