how to write a debug.ini to simulate 4*4 keypad conntected with P1??

i write a function ,but it not works at all..
how can i do?
signal void key_s1()
{ while((P4 &0x0f) != 0) { twatch(10); }

P4 &= 0x0f; twatch(200); P4 |= 0xf0;

while((P4 &0x0f) != 0) { twatch(10); }

P4 &= 0x0f; twatch(200); P4 |= 0xf0;

}