I have written a small function as below: void checkKeyPress() { uchKeyPressed = P1; /* Read Port P1 */ uchKeyPressed = uchKeyPressed & 0x18; /* mask with 0x18 to check for P1.3 & P1.4 */ } /* end of function void checkKeyPress() */ void main() { do { checkKeyPress() } while (uchKeyPressed != 0x08); } /* end main */ I want to simulate the input from port P1 in the debugger. How can I do it? Also if I want to simulate an input say from 8279 address 0xc001, how can we do it in the debugger? Regards, Mohit