I'm trying to use my RDM6300 module with the Raspberry Pi 3 as show on this site: https://behindthesciences.com/electronics/raspberry-pi-rfid-tag-reader/

I disabled the terminal tty by putting in /boot/config.txt


I wired the module to 5V, GND, GPIO 8 and 10 (BCM 14 and 15) but I can't still communicate with the module using the serial port. I'm using this python script

import time, serial

sl = serial.Serial("/dev/ttyS0", 9600)

while True:
    ID = ""
    read_byte = sl.read()
    if read_byte == "\x02":
        for i in range(12):
            read_byte = sl.read()
            ID = ID + str(read_byte)

and the kernel 4.9.78-v7+

  • With linux 4.14.18-v7+ the serial port is now working fine.
    – Marco
    Feb 19, 2018 at 18:47
  • I am having the same issue and tried to follow the answer below with no luck. Did you end up using ttyS0 or serial0? I have linux version > 5. Are there any other configuration issues you found that you needed to change? Sep 12, 2021 at 7:55
  • Hi @russelrillema . Honestly, I have no idea. The system was in prod with the same kernel up to few months ago, when was dismissed. Sorry!
    – Marco
    Sep 13, 2021 at 8:04

1 Answer 1


Have you try to the see list of peripheral in ls /dev?
Have you try sl = serial.Serial("/dev/serial0", 9600)?

  • Alright, i can see /dev/serial0 and /dev/serial1 but no one is receiving data from the module (i near the key and nothing is shown either via minicom)
    – Marco
    Jan 31, 2018 at 17:51
  • Do you have invert RX and TX?
    – 2CoB9
    Feb 1, 2018 at 9:37
  • Try to delete console=serial0,115200 in /boot/config.txt
    – 2CoB9
    Feb 1, 2018 at 9:38
  • Yes i tried to invert RX and TX without any result. I have no console=serial0,115200 neither in /boot/config.txt nor in /boot/cmdline.txt . Loopback is working fine (connecting RX and TX togther) and the same module on my Sunfounder mega is working fine too.
    – Marco
    Feb 1, 2018 at 14:59
  • serial.Serial("/dev/serial0", 9600) worked for me using the python3-serial package
    – Sven Rojek
    Aug 16, 2018 at 22:08

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