Assign Serial I/O to a PC COM Port

The ASSIGN command allows you to use a PC COM Port as input for an UART 
in the uVision Simulator. If you enter the following commands, serial 
I/O is performed via the COM2: interface of your PC. 
The STIME variable allows you to ignore the timing of the simulated
serial interface.

>MODE COM2 9600, 0, 8, 1        /* 9600 bps, no parity, 8 data & 1 stop bit */
>ASSIGN COM2 <S0IN >S0OUT       /*ASC0 output & input is done with COM2:*/
>S0TIME = 0                     /*ignore timing of simulated ASC0 interface*/