Hello

I work with a MKE18F512 and I have to use the ADC.

We work with 5V Supply and a external 5V Ref

Now I have the problem that the any ADC pin is at 2,5V and delivers up to 20µA out current.

Could this be correct?

Why are the ADC pin at 2,5 in idle position.

To test this problem I have disconnect all connections form the ADC pin but it stays at 2,5V if the ADC run.

I am happy about any idea.

regards

Tobias

Hello

now we have found a reason for our problems.

The security resistor for the ADC, with 10kOhm, is to big.

If we use a 100Ohm resistor we don't have this problems, the voltage drop is lower with the 100 Ohm resistor.

I have done a test with the demoboard and the potentiometer and better measurement units.

First I changed the example to use 12 bit ADC result and 16bit hardware average.

Then I replaced jumper J9 with a resistor.

10kOhm: ADC => Min 271 ... Max 3998

100Ohm: ADC=> Min 0 ... Max 4094

Jumper: ADC=> Min 0 ... Max 4094.

Thank you four your help.

Tobias Härter