I’m trying to create an application on KL03 FRDM which uses CMP0 to detect a signal and generate an interrupt. I configured the DAC output as negative input and a pin (PTA12) as positive input. I’m using KDS and Processor Expert.
The problem is the pin which should be the positive input pin has a voltage level of 3V. So it is impossible to detect a rising edge in my signal. Only if I connect the pin to GND and disconnect it again, an interrupt is created because the pin value returns from 0 to 3V. And PTA12 is not the only Pin with a fixed output voltage, there are several others as well.
Why is there 3V output on an input pin? Do I have to configure the input pin somewhere else than in the COMP-component as well?
Any help is appreciated