dear friends i have a peculiar situation at hand . i am trying to dump some message to my serial port and see it through my dummy terminal . before that i tried a simple LED toggling , it worked fine . for that the code i had written is : #pragma small #include<AT89X51.h> #include<stdio.h> int main() { TMOD = 0x20; // The timer set to 8 bit auto reload timer TH1 = 0xFD; // Higher byte of timer1 set to FD or reload value set to FD TL1 = 0xFD; // Lower byte of timer1 set to FD SCON = 0x52; // The serial Controller is configured TR1=1; // Timer 1 run flag set while(1) { printf("Hello World \n"); // data sent to serial port for displaying } return 1 ; } so the problem is that on my hyperterminal i dont get anything . but in debug window ,in the serial watch window , i am able to see the output . but after burning the code into the chip and subsequently in the hyperterminal i am not able to . i am not able to follow where lies the problem . in the c51 primer exact code has been given , but that too does not work . plz help .ASAP with regards Som