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    Core 2 unit with M5Go2, Serial Port C and external Elechouse RFID V 1.2

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    • F
      falbriard
      last edited by

      On a Core 2 unit with M5Go2 bottom, I need to connect an external RFID board (Elechouse) but its not working yet, just getting a "None" or b'x\00' data return.

      The connection is UART based using Port C (Blue), Pins TXD2 14, RXD2 13 : Supports UART with 115200 data rate configured to UART2). In order to test the Core2 side I did loop configuration sending RX to TX with a jumper wire and I worte a string "Testing_Serial" by an UART write command. This worked fine. When connecting the external board I get back a string with b'x\00'. The wires to the external device are crossed TX->RX, RX<-TX and the two power wires. Not sure, if there is a command sequence required to activate the data transmission and RFID data readout at the device. The board is reading tags and is blinking. Any insight are welcome.

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      • felmueF
        felmue
        last edited by

        Hello @falbriard

        do you have a link to the specifications of the Elechouse RFID v1.2? The ones I found from Elechouse (which support UART) state in the specification that UART TTL interface is 5 V. While Port C power is 5 V the data lines TX and RX are only 3.3 V. Maybe that is the issue?

        Thanks
        Felix

        GPIO translation table M5Stack / M5Core2
        Information about various M5Stack products.
        Code examples

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        • F
          falbriard @felmue
          last edited by

          @felmue You are right, it seems to be a voltage mismatch. The UART requests 5V, but ESP32 delivers only 3.3V.
          Reading: "On-board level shifter, Standard 5V TTL for I2C and UART, 3.3V TTL SPI"
          Find more: https://manuals.plus/elechouse/pn532-nfc-rfid-module-manual#introduction
          Time to buy a M5stack reader unit and use the standard UiFlow drivers. Thanks!

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