hello !!
i made a programmer for AT89S52. code is given below. the programmer is showing the desired pattern on a LED being plugged into the port but its not programming the chip.the hardware is a simple circuit with a 40pin ZIF socket and RST permanently on. other components like crystal, oscillator are proper. in short,the hardware has no problem.
what may be the problem? is it something to do with the port output voltage?


#include<stdio.h>
#include<conio.h>
#include<dos.h>

# define PORT 0x0378
void main()
{
clrscr();
FILE*fp;
int i;
char a,b;
int c[4];
fp=fopen("hex.txt","r"); /* code to be bunred in hex */

while(1)
{
a=fgetc(fp);
if(a==EOF)
break;
else
{
if((a>=48)&&(a<=57)) /* hex to bin*/
a=a-48;
else
{
if((a>=65)&&(a<=70))
a=a-55;
else
{
if((a>=97)&&(a<=102))
a=a-87;
else
{
printf("invalid code");
break;
}
}
}
for(i=0;i<=3;i++)
{
b=a/2;
c[i]=a%2;
a=b;
}
for(i=3;i>=0;i--)
{
if(c[i]==0)
{
outportb(PORT,00000000);
delay(100);
outportb(PORT,10000000);
delay(100);
outportb(PORT,00000000);
delay(100);
}
else
{
outportb(PORT,01000000); /* 1st digit for clock*/
delay(100);
outportb(PORT,11000000); /*2nd digit for data*/
delay(100);
outportb(PORT,01000000);
delay(100);
}
printf("%d",c[i]);
if(a==EOF)
{
fclose(fp);
break;
}
}
}
}
getch();
}

please reply soon.