Problem in interfacing RFID module with AT89C51, need help !

[Shafie]

 

I have interfaced this RFID module with AT89C51 micro controller:

 

seeedstudio.com/wiki/125Khz_RFID_module_-_UART

 

using the instructions and codings given here:

 

engineersgarage.com/microcontroller/8051projects/interface-rfid-AT89C51-circuit

 

but when I scan a RFID card, it appears some numbers & chinese letters as “UNIQUE CARD ID:”, even it getting changed randomly each and every time i scan – the same card !.  May I know what is the problem ? do I have make any changes to make this circuit function correctly ? 

 

 

[AJISH ALFRED]

 

Please note that in your RFID module pin1 is the TX pin and it should be connected to pin13 (RX pin) of the max232.

Leave the pin 2 of the module unconnected as it is RX pin.

[Shafie]

//Please note that in your RFID module pin1 is the TX pin and it should be connected to pin13 (RX pin) of the max232.

Leave the pin 2 of the module unconnected as it is RX pin.\

 

I did and getting the same result !!! , any other solution ?

[AJISH ALFRED]

 

Hi Shafie,

 

Make sure you’ve set the baud rate at 9600.

Have you checked your module with hyperterminal?

Are you using same power supply for the module and mcu? If not short the ground of both.

Check your max 232 –

short the tx and rx pin of max232 that goes to the mcu, disconnect the reader and connect the serial cable from the pc, and type something on the hyperterminal, use should get the same characters back in the hyperterminal.

[AJISH ALFRED]

 

Hi Shafie,

                Your RFID module is ttl compatable, no need to use a max232. You can directly connect it to the mcu.

 

Find an example on this link

http://www.instructables.com/id/Arduino-and-RFID-from-seeedstudio/?ALLSTEPS

 

I hope this will help you to fix the problem

[Author]

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