How to define UART RX pin in initialization? Should we define as alternative function push-pull or floating pin? And why?

[NArsl.1]

We are using STM32F103VCT6 in our projects. We are communicating through RS-485. When we initialize RX pin as alternative function push-pull there occurs a voltage drop on RX pin voltage level. We are curious about UART peripheral GPIO diagram. And would this situation cause a damage on the communication IC?

[waclawek.jan]

The 'F1 family is different from all other STM32 families in that it has a much simpler GPIO structure. In all other STM32 families, the peripheral determines the direction of pin, in STM32 user has to do this individually for each pin:

JW