I wrote the code for it in keil.The simulation worked perfectly but the hardware implementation for the same is not working properly.Please help
< #include<reg51.H> sbit IN = 0x91; sbit OUT = 0xA1; void main() { P1=0xFF; P2=0x00; while(P1_1==1) { P2_1=1; } while(P1_1!=1) { P2_1=0; } }
You haven't even included any delay in the program. The crystal oscillator, which i assume is of 11.0592MHz or 12MHz. At such a high frequency, the time period is 1 micro seconds. DO you think for such low time period, you will see the LED TURN ON? I think you won't. So you have to Turn ON the LED and give a big Delay which is atleast more than 250milli seconds.
The main loop also terminates. why?? In assembly, dont we write this at the end of the code?
SJMP $ or LOOP: SJMP LOOP
Use a infinite loop at the end of main so that main does not terminate.
Read this book "8051 microcontroller and embedded system by Muhammad Ali Mazidi" The program for LED BLINKING is already written for you. Or else GOOGLE.
Note that delays aren't needed for this construct - the program is intended to mirror the state of a switch. And to make it work, the program should not have a while loop at end of main() - it should have the while loop encapsulate the code that checks the switch and decides if LED should be on or off.
Yup. Per is Right.
My suggestion was intended to just get the LED ON and OFF (independent of the status of the switches). To ensure LED turn On and turn OFF is successful, hence the hardware is working.