i've changed 48 to '0'...
i don't get it... sometimes it reads the data correctly sometimes it doesn't. i don't find a rule here...maybe i'm missing something
when the data readen is wrong, each time it's wrong it's the same...it's not something random!


#include <reg51.h>
#include <stdio.h>

//extern void init(void);
unsigned char port1;
//sbit p3_b7 = port3 ^ 7;
unsigned char nrb=0;
unsigned char byte_meu[40];
unsigned char i=0;


void alarm (void) interrupt 2 //enters when clock signal comes from card reader
{
if (i>30) EA=0;//after 30 characters we stop the interrupt
port1=(~P1)&0x01; //reading data pin from P1, bit 1
byte_meu[i]=byte_meu[i]<<1;
byte_meu[i]=byte_meu[i]+port1; //writing in a byte
nrb++;
if (nrb==5){ //go to the next location after 5 bits
i++;
nrb=0; //reset bit counter
}
}

init_all() //serial init
{
SM1=1;
REN=1;
TMOD=0x20;
TH1=0xFD; //=253
TR1=1;
EA=1;
EX1=1;
IT1=1;
P1=255;
P3=255;
}


void main (void) {
char c;
unsigned char j;
init_all();
printf ("Hello World!!\n");
while1:

c= _getkey (); //wait for key
printf(" i:%d \n",i);
for(j=0;j<40;j++)
{
putchar ( byte_meu[j]+'0'); //send the data when key is pressed
byte_meu[j]=0x0; //clear the data after we send it
}


nrb=0; //clears number of bits and
i=0; //number of caracters read
EA=1; //enables interrupt

goto while1;

}