Problem with AD inputs at PIC16f873a

[wurm]

Hi,

I have a problem with a Pic16f873a.
I´m using 4 of the 5 analog to digital converts. Every AD port is with a resistor pulled down.
On Port c I have 4 outputs with LEDs.
As you can see on Beispiel1.bas I read ad channel 0 to 3 and when there is a value bigger than 0 the Led on the output changes to high.
This works for all of the 4 channels.

Now I`ve changed the program (see Beispiel2.bas)
On AD channel 0 the Led only get high when on the input a signal with 2.5V exists.
Now, when I put a signal bigger than 0V on any of the 4 AD inputs, all of the 4 output Led gets high.
I can´t understand this. I´ve tried various ADCON0 and ADCON1 and Sample-times without any other result.

Does somebody know, what here is wrong?

Best regards,
Thorsten Wurm