Question regards to the Pin C0 on PIC18F8720 as input???

[Jimmy]

Hi,
I use pin C0 to detect the close/open event of switch. I have it connect as follow:

5v <---------------R=10K------------------> Pin C0
|
|
|--------Switch-----> Ground.

Usually , when the Switch opens, I see almost zero voltage dropped throught the resistor R=10K, but there is a development board, I see all most 2.5 voltage dropped through the resistor when the switch is open which means that Pin C0 is sucked in some current??? WHy does this happen??? Does this mean that Pin C0 is broken on this board???

Thank

[Jimmy]

Correct the last post:

Hi,
I use pin C0 to detect the close/open event of switch. I have it connect as follow:

5v <---------------R=10K------------------> Pin C0
|
|
|--------Switch-----> Ground.

The one end of the switch is connected betweet resistor and Pin C0

Usually , when the Switch opens, I see almost zero voltage dropped throught the resistor R=10K, but there is a development board, I see all most 2.5 voltage dropped through the resistor when the switch is open which means that Pin C0 is sucked in some current??? WHy does this happen??? Does this mean that Pin C0 is broken on this board???

Thank

[Guest]

Hi,
sorry, I have some problem with the text format, so the drawing does not look right!
I should draw it this way:

5 volt
|
|
-
Resistor = 10k
-
|
|
|
|
|--------------->Switch------------->Ground
|
|
|
|
Pin C0

Oh, another note, when it first power up, it seems ok, by default, the switch is close and Pin C0 is low, but after I open the switch one time, it keep staying high all the time, even when I close the switch...and It seems that Pin C0 draws some current and there is voltage dropped through the resistor( about 2.5 volts)

JIm