UART-hyperterminal interface in verilog code

I think you are trying to do too much at once. Start out with a simple rx/tx uart (rx first, then tx) and then add features to it. We don't even know if you are using an RS232 voltage level convertor properly. Also make sure you write a good testbench and build it as you add functionality. This is the only way to tackle designs, especially one like this which can be broken down easily into multiple independent functions. Look up the spiral approach to software development. set up another PC if you can and just have that PC talk to and fro with hyperterminal by switching tx/rx signals . In this way you can systematically build your application up.