TTL interface of swipe card reader

mydata[i] & mask = dat;

That is not valid 'C' - the expression is not valid for the left-hand side of the '='

HAI,
Thanx for your fast reply . How its possible in C ,how can i sotre bit stream data?

If your code works in simulator & not in actual circuit, most probably your circut has different timings.
Ive' have ot got the code and cannot see the problem(havn't run it), here are my suggesitions,
1) Make sure you wait atleast 30mSec before it's initialization is started.
To be on the safer side use more delays than what they specifies.

Hope that helps. If you still having problems I'll post a example with C which you can easily convert to ASM.

I am affraid that you can't use complete C code, as the async data from Card reader will be coming at much faster rate than the code execution time.

Attempt to write in ASM and integrate in the 'c' main:
-Init. & Reserve arrray of IDATA
-Use bitwise operators to store seq. in IDATA

You have varies ways to make this idata available in global scope.

did you mean

mydata[i] = dat & mask ;

?

If it's data from a standard track 2 interface and your processor is running at a reasonable rate (>7MHz) then you will easily be able to write the ISR in C.

You might find it easiest to have a 'storage index' and a 'bit mask' to write each bit to a buffer. Much as 'S Edara' suggests.

if (Tamirre> Michael)
  NameChanged();
else
  SimpleTypo();

Ah Kalib Rahib, welcome back! Thanks for the correction. If you could only persuade Eric to change his name to "Sir Erac"... :-)

Thanks Flaver, I have not done my home work on the speed.

"If you could only persuade Eric to change his name to "Sir Erac"..."

you be know some my freinds stil need picture of theyre goodly idal Erac. we see google and facebook but no be getting :(

Have you tried "myspace" ? :-)

Hai Friend,
My code get some compilation error as mentioned in my first post. So the problem I think is not in hardware, but in code itself. If I get a single bit from a card, then it is possible to store in a single bit. But if it is a stream of bits, then I have to store in a bit array. How can I define a bit array and how its bits can be accessed.
Actually there is 8 bits in a char, but I am not able store a bit in its bit0 or bit1 etc.
Is it possible using Keil to store a stream of bits to such a variable. Is it possible to use bdata variable for this purpose?
Please help me with a sample code.

C doesn't has any bit arrays.

Standard C programming can allow you to use a byte array to store any sequence of bits. All you need are the shift operations << and >> together with bit-and & and bit-or |.

To insert five bits at a time, you can keep two variables.

Current start byte to write in. (0 .. sizeof(array))
Current bit position to write in. (0 .. 7)

if bit offset is 0: write only in first byte and increment bit offset by 5.

if bit offset is 1: write only in first byte and increment bit offset by 5.

if bit offset is 2: write only in first byte and increment bit offset by 5.

if bit offset is 3: write only in first byte. then increment byte offset and set bit offset to 0.

if bit offset is 4: write four bits in first byte. then write 1 bit to start of second byte. increment byte offset and set bit offset to 1.

...

if bit offset is 7: write one bit to first byte. then write 4 bits to start of second byte. increment byte offset and set bit offset to 4.

The above can be merged into quite few lines of C code, and is left as an exercise.

Note that writes to the first byte may require a shift left to skip a number of bit positions. Writes to the second byte may require a shift right, to throw away already written bits.

If a 16-bit processor was used, it would normally be efficient to have a 16-bit variable where the data is shifted in, and whenever it contains >= 8 bits of data, then one byte is written. This of course also requires that the transfer is finalized by inserting dummy bits after the transfer, until a full byte is available for storing.

HAI,
How can I acess a single bit from a character and store a bit into that location ? can you please post a simple example of that.

Access:

(*Store) & (1<<BitNumber);

Store:

if (BitVal==0)
  *Store &= ~(1<<BitNumber);
else
  *Store |= (1<<BitNumber);

BitNumber is a value 0 to 7.