I am looking for connecting to ADAFRUIT RFID PN532 readers to one arduino, I think its possible since I2C was for that, but how can i modify the code (Which is already in RFID ADAFRUIT LIBRARY) two access through the both readers at one instance ?
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1 Answers
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No, you can't connect two Adafruit PN532 shields on the same I2C bus. The problem is that you can't change the peripheral address of the PN532. Thus, both PN532 NFC chips would respond to the same address and you can't control which of the two shields you communicate with.
However, you may be able to separate the two boards
- by using an I2C multiplexer that switches between the two boards, or
- by using the SPI option of the PN532 shields. In SPI mode you have an additional chip-select PIN that you could wire to separate PINs of the Adruino. You could then address a specific PN532 shield using those chip-select lines. However, you would need to port the PN532 library to SPI communication.
