a liitle knowledge about RFID

[Kinshara]

I am trying to read from RFID tag from reader-12,
but I have no idea what is the first thing I must learn..
must I try serial port first? and how can I get the value from the tag?
any example or tutorial?
Thanks

[Salem]

How To Ask Questions The Smart Way
Is there anything in your post which enables us to accurately and quickly identify the device that you have?

> must I try serial port first?
No idea.
It would be a waste of time if your device plugs into the USB though.

> and how can I get the value from the tag?
*shrug*

> any example or tutorial?
...
> but I have no idea what is the first thing I must learn..
The first thing you must learn is how to use a search engine.
Step 1 - type in the manufacturer (and perhaps model number) of the device you're interested in
Step 2 - add keywords like "SDK" "programming" "development"
Step 3 - add keywords like "source code" "examples"
Sooner or later, you'll stumble into the manufacturers website aimed specifically at developers who want to develop software and solutions using their particular device. It's in THEIR interest that such information is available, since the more people who develop applications for it means more hardware sales for them.

Having found the right site, download and read every technical note, application note, how-to or anything else which might seem relevant to the problem (and hardware) at hand.

They may even have a forum such as this, just for helping would-be developers to get up and running.

[iMalc]

Would that be this device: https://www.sparkfun.com/products/8419
I know a lot about RFID as I work with it quite often at my workplace. Heck I can even tell you how they work, and know much of what one needs to know to build a reader.
But it turns out that you haven't provided much useful information for us to help you.

[Kinshara]

yeahhh..
I havent got any idea until now x_x

I am using visual studio 9..

#include <windows.h>
#include <stdio.h>

int main(int argc, char *argv[])
{
   DCB dcb;
   HANDLE hCom;
   BOOL fSuccess;
   char *pcCommPort = "COM2";

   hCom = CreateFile( pcCommPort,
			GENERIC_READ | GENERIC_WRITE,
			0, // must be opened with exclusive-access
			NULL, // no security attributes
			OPEN_EXISTING, // must use OPEN_EXISTING
			0, // not overlapped I/O
			NULL // hTemplate must be NULL for comm devices
			);

   if (hCom == INVALID_HANDLE_VALUE) 
   {
       // Handle the error.
       printf ("CreateFile failed with error %d.\n", GetLastError());
       return (1);
   }

   // Build on the current configuration, and skip setting the size
   // of the input and output buffers with SetupComm.

   fSuccess = GetCommState(hCom, &dcb);

   if (!fSuccess) 
   {
      // Handle the error.
      printf ("GetCommState failed with error %d.\n", GetLastError());
      return (2);
   }

   // Fill in DCB: 57,600 bps, 8 data bits, no parity, and 1 stop bit.

   dcb.BaudRate = CBR_57600;     // set the baud rate
   dcb.ByteSize = 8;             // data size, xmit, and rcv
   dcb.Parity = NOPARITY;        // no parity bit
   dcb.StopBits = ONESTOPBIT;    // one stop bit

   fSuccess = SetCommState(hCom, &dcb);

   if (!fSuccess) 
   {
      // Handle the error.
      printf ("SetCommState failed with error %d.\n", GetLastError());
      return (3);
   }

   printf ("Serial port %s successfully reconfigured.\n", pcCommPort);
   return (0);
}

this is the simple code I got when I was searching, but all I got an error
createfileW cannt conver parameter 1 from 'char *' to 'LPCWSTR'

[Click_here]

Have a look at these

winapi - C basic datatype problem - const char * to LPCTSTR - Stack Overflow
C code help
CreateFile function (Windows)

[stahta01]

You NEED to set the correct baud rate; not pick one at random!

dcb.BaudRate = CBR_57600;     // set the baud rate

Tim S.

[Kinshara]

Have a look at these

winapi - C basic datatype problem - const char * to LPCTSTR - Stack Overflow
C code help
CreateFile function (Windows)

ohh I got it now