Using serial port C on RCM3200 at non-RS232 levels


May I ask how can I disable RS232 levels for Serial Port C on a RCM3200 rabbit core module? So that I can tap my input/output directly from PC2 and PC3 without interference from the RS232 driver circuit.

Currently, I observe that PC2 and PC3 are both high when at rest states. This brings me to think that PC3 can’t be an input port, even though it has been initialized as an input port.

Are there any high impedance input port which I can use to input serial data at non-RS232 levels?