I will use ATmega48PA-AU CPU as the core. So I will have only one USART port at the CPU end.
One of important assumption is that only one interface will be used at one time.
What I intend to do is to use diode-diode decoupling for RxD line:
I expect that this schematic should work for low frequencies (9600 in my case). But I've never used FT232BM chip in particular, moreover I've never designed any device with USB interface. So some troubles I'm not aware of can surprise me. Is there any?
And is there any better cheap and simple solutions for decoupling interfaces for such case?