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PSoC 5, 3 & 1 MCU

New Contributor II

 "NC" no connect pins on PSOC5-LP are internally not connected? Can i connect these pins to any signal or voltage?

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Esteemed Contributor

No, not any signal, you still have to meet allowed input levels because

   

of parasitic elementrs in the CMOS structure. So basically meet (from

   

datasheet) -

   

 

   

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New Contributor II

"NC" pin not a GPIO and VNC isn't specified in datasheet. Probably it's internally not connected. If it so, it can connect to higher or lower voltages than supplies. Anyway, I want to NC pins connect to GND. I want to be sure Is it problem or not.

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Honored Contributor II

The general rule for NC pins is to not connected them, since usually there is no information about whats inside of them. Is there a special reason why you want to connect them?

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New Contributor II
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New Contributor II

i can't see my previous post. i send again.

   

   

This is my layout. Bright pads are GND.  37-39 VCC.  All passives decoupling CAPs. 40-41 NC pins.

   

   

This ground plane bad. (pin38 and right side of layout GND).

   

   

if pin41-42 connect to GND, GND plane is better. This is why i want to connect GND and NCs.

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New Contributor II

   

    

   

               

   

This ground plane bad. (pin38 and right side of layout GND).

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Esteemed Contributor

My apologies, I was thinking unused pins vs NC. Clearly there must be some limitations,

   

even if pin not bonded to die. Isolation, HV standoff, crosstalk......

   

 

   

I would file a case, and point to this thread, When you get an answer post

   

results.

   

 

   

    

   

          

   

To create a technical case at Cypress -

   

 

   

www.cypress.com

   

“Support”

   

“Technical Support”

   

“Create a Case”

   

 

   

You have to be registered on Cypress web site first.

   

 

   

   

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Esteemed Contributor

My apologies, I was thinking unused vs NC. Clearly there should be some limitations

   

on a NC pin, HV standoff, Isolation, crosstalk.....even if pin not connected to die.

   

 

   

I would file a case and post the response -

   

 

   

    

   

          

   

To create a technical case at Cypress -

   

 

   

www.cypress.com

   

“Support”

   

“Technical Support”

   

“Create a Case”

   

 

   

You have to be registered on Cypress web site first.

   

 

   

Regards, Dana.

   

   

 

   

 

   

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Esteemed Contributor

Found this -

   

 

   

    

   

          http://www.cypress.com/?id=4&rID=26486

   

 

   

Regards, Dana.

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New Contributor II
Answer of Cypress Technical Support; NC stands for "No Connect" which means that the pin is not internally connected to the die. So it can be either left floating or tied to GND or tied to VCC. 
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New Contributor II

 Interesting, if these pins are not connected with anything, what purpose for they are routed to P4 socket and test points on CY8CKIT-001 and CY8CKIT-010? Is there a secret function we do not know?

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Honored Contributor II

Maybe because all pins of the PSoC are routed to the port connectors. That way, when a PSoC device with more available pojns come out the routing doesn't change.

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