<![CDATA[Core 2 unit with M5Go2, Serial Port C and external Elechouse RFID V 1.2]]>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.

]]>https://community.m5stack.com/topic/4575/core-2-unit-with-m5go2-serial-port-c-and-external-elechouse-rfid-v-1-2RSS for NodeThu, 05 Mar 2026 15:24:59 GMTThu, 01 Sep 2022 14:19:28 GMT60<![CDATA[Reply to Core 2 unit with M5Go2, Serial Port C and external Elechouse RFID V 1.2 on Thu, 01 Sep 2022 17:00:38 GMT]]>@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!

]]>https://community.m5stack.com/post/18517https://community.m5stack.com/post/18517Thu, 01 Sep 2022 17:00:38 GMT<![CDATA[Reply to Core 2 unit with M5Go2, Serial Port C and external Elechouse RFID V 1.2 on Thu, 01 Sep 2022 15:24:04 GMT]]>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

]]>https://community.m5stack.com/post/18516https://community.m5stack.com/post/18516Thu, 01 Sep 2022 15:24:04 GMT