LPC55S28 - connecting unused pins

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

LPC55S28 - connecting unused pins

706 Views
ranjeetm
Contributor I

Hi - We are looking to use the LPC55S28 device and do not intend using external Crystal or the USB interface. Is there a Hardware Checklist available which provides guidance as to how to connect the Unused pins.

thanks

regards, 

Labels (1)
Tags (1)
0 Kudos
3 Replies

640 Views
Omar_Anguiano
NXP TechSupport
NXP TechSupport

Hello Ranjeet Malhotra

 

Under chapter 6.1.1 you can find a table that shows how to terminate pins that are not used in the application https://www.nxp.com/docs/en/data-sheet/LPC55S2X-LPC552X.pdf

 

pastedImage_2.png

 

Let me know if this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar

0 Kudos

640 Views
ranjeetm
Contributor I

Thanks - that was very helpful. A follow up question - can any of the GPIO lines of the Microcontroller be connected to a signal when the device itself isn't powered? We are specifically looking to connect one of the Flexcom's to another system using I2C and do not have any control over power sequence. There will be instances when the other system may get powered first and provide signals on the I2C lines while the Microcontroller is not powered. Will the I/O pins get damaged? Do we need to isolate the bus?

regards, Ranjeet

0 Kudos

640 Views
Omar_Anguiano
NXP TechSupport
NXP TechSupport

Hello Ranjeet Malhotra

 

Analog pins are more susceptible to damage in this circumstances, digital pins have some protection circuitry, however, I suggest to isolate the pins if the pins will be receiving signals when the MCU is off in order to avoid any damage.

 

Let me know if this is helpful, if you have more questions do not hesitate to ask me.

Best regards,

Omar

0 Kudos