Referring to the MFRC522 RFID Reader/Writer rfid reader writer module. How do I configure its UART so it can talk to an rs232 port of a PC?

The answer is probably similar to this question


which point out that it not easy to write PC software (not suprisingly) for a arduino module with same interface. So the question is then -is there an existing PC software for this?


1 Answer 1


There's an existing Arduino library that uses the module's UART interface, rather than the more common SPI. It provides basic methods for reading the UID of a card and R/W operations on blocks. You could easily port that library to your favourite PC programming language, connect the module to your PC probably through some USB-UART adapter and get to work.

If your PC has an actual TIA-232 serial port and you want to use that to talk to the module, you'll need a driver like the MAX232 to sit between the module's TTL UART and the PC serial port.

Use this as a guide:

enter image description here

All GNDs must be connected together.

  • \$\begingroup\$ I am new to hardware and would like a circuit diagram. What are the circuit diagrams for the rs232 answer you mention? And yes, my desktop PC does have an RS232 port on it. \$\endgroup\$ Commented Nov 1, 2016 at 9:13
  • \$\begingroup\$ Do you need four pins rather than three for rs232 connection for this module? \$\endgroup\$ Commented Nov 1, 2016 at 10:45
  • \$\begingroup\$ Four or three pins?-what the exact circuit to interface to rs232?-I dont think the answer is that easy too \$\endgroup\$ Commented Nov 2, 2016 at 11:55
  • \$\begingroup\$ @yabbadabba You only need 3 pins for UART. See my edit. \$\endgroup\$ Commented Nov 2, 2016 at 12:09
  • \$\begingroup\$ I get the general idea of you guide solution and why an max232 maybe needed. But maybe I misunderstood something -I thought UART was not the same as RS232 -so it doesnt make sense to me to say it needs 3 pins. I thought maybe the DTR line maybe needed. \$\endgroup\$ Commented Nov 2, 2016 at 15:14

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