Hello All,

I created a hex file with the following code in Keil and downloaded to 89C52 chip.

#include <stdio.h>
#include <at89x52.h>

void nothing();
void main()
{
int i = 0;
P0 = 0x00;
P1 = 0x00;
P2 = 0x00;
P3 = 0x00;

for(i = 0; i < 200; i++){
P2_6 = 0x80;
nothing();
P2_6 = 0x00;
nothing();
}

for(i = 0; i < 200; i++){
P2_5 = 0x80;
nothing();
P2_5 = 0x00;
nothing();
}

while(1){
P2_7 = 0x80;
nothing();
P2_7 = 0x00;
nothing();
}
}

void nothing()
{
int i;
for(i = 0; i < 0x5000; i++);
}

Now the problem in the Keil simulator the code works fine, but when loaded onto the chip only the first loop executes. I have connected 3 LED's to P2_5, P2_6, P2_7. So the LED connected to P2_6 blinks for the given count, but after sometime it continues to glow and no other LED Glows as per the code. What could be the problem.

Does it have anything to do with the code optimization level set.

Thanks & Regards
Rajmathi