My Virtex II Pro board is connected to the hyperterminal through RS232. My VHDL code receives a character from hyperterminal, then sends back to hyperterminal. The problem is that the returned character is diferrent from the typed character. For example, when I type "a", I get "h" as returned character, consistently.
It seems that the four most significant bits stay the same and only the four least significant bits change. I am 100% sure my transmission code is ok. Also, testing RS 232 cable (using Oscilliscope), the same typed character enters the board. The problem must be in RX code.
Any idea or experience with this kind of problems ? Thanks