Seperate analog inputs reading the same value

Hello.

I have the analog inputs example set up, http://arduino.cc/en/Tutorial/AnalogInput; but have 'pin 3' of the potentiometer connected to analog input 2 instead of ground, to divide the signal between the two inputs; or so I thought.

For some reason both inputs read almost the same value, just a little below 1024 regardless of potentiometer setting, and I can't understand why.

Google reveals somewhat flaky information about 'ghosting', to do with the fact that there is a single ADC with a multiplexer; so I've tried grounding the remaining analog inputs as described on one of the results, but this hasn't fixed the problem.

Code:

Defines:
#define ANALOG_INPUT_PIN_1 0
#define ANALOG_INPUT_PIN_2 1

In main loop:
sdcIOStatus.nAnalogInput1 = analogRead(ANALOG_INPUT_PIN_1);
sdcIOStatus.nAnalogInput2 = analogRead(ANALOG_INPUT_PIN_2);

Nothing relevant in initialisation.

Try this:

sdcIOStatus.nAnalogInput1 = analogRead(ANALOG_INPUT_PIN_1);
sdcIOStatus.nAnalogInput1 = analogRead(ANALOG_INPUT_PIN_1);
// use the 2nd value

sdcIOStatus.nAnalogInput2 = analogRead(ANALOG_INPUT_PIN_2);
sdcIOStatus.nAnalogInput2 = analogRead(ANALOG_INPUT_PIN_2);
// use the 2nd value

If your source has really high impedance, like a 100K series resistor in series with the output, then you have to allow more time for the signal to charge the on-chip sample & hold capacitor before the conversion.

No avail unfortunately, not even if I space them out with 100ms delays.

I'm using a 1k pot with a 330ohm resistor in line with each input.