Interesting observation with Pin.

[Anonymous]

 Hello 

   

In the topdesign, I have a input pin connected to ISR. I have kept intrerrupt trigger for falling edge and initial state is 1(high). But the pin is acting something similar to proximity or just touch button. As soon as I move my finger close to the button I am receiving an interrupt. New discovery!!!!!!! LOL.

   

Any reasons why is it so?

   

Akash

[Bob_Marlowe]

Change the pin drive mode to pull-up or pull-down. A High-Z pin REALLY IS High-Z The disturbances picked up by your body from power-lane is quite sufficent to drive a High-Z pin to any level.

       

Bob

[HeLi_263931]

Just for testing - you can use an external pullup resistor too.

[Anonymous]

 That was very helpful........If this is the case then probably can we not develop a solution which is a touch based solution.

[Bob_Marlowe]

This is already done and it is named CapSense.

   

Just to narrow or even touch a pin might destroy the chip in case of a static electric discharge. When you touch the measure-Tip of an oscilloscope you can see that the voltage goes up to 400V.

       

Bob