iam Beginner to PI3 iam facing one problem in the Raspberry Pi3

currently i want to do serial Communication on the UART pin 14 and 15, where i have done loopback, Problem i faced is iam not able to send any data

Task done As Raspberrypi3 ttyAMA0 is assigned to bluetooth , so iam using the ttyS0 ,where iam using gtkterminal for configuring the port and send the data

by help of website help , i changed the config.txt by including the Enable_uart=1,core_freq=250 and even though non of the data is flowing

so kindly any one can help me to solve this problem

  • Could you post a photo of the loopback over 14/15? Pins 14/15 are not the UART. Pins 8/10 are the UART, Do you mean GPIO 14/15? A photo will remove ambiguity.
    – joan
    Commented Jan 20, 2017 at 12:49
  • Have you enabled serial? See How-do-i-make-serial-work-on-the-raspberry-pi3 NOTE it is enable_uart=1 check if /dev/serial0 exists
    – Milliways
    Commented Jan 20, 2017 at 23:11

1 Answer 1


if you're not using Bluetooth you can disable it or switch the ports by adding pi3-miniuart-bt or pi3-disable-bt. check /boot/overlays/README and run this systemctl disable hciuart. I just disabled Bluetooth on mine and got back "ttyAMA0" everything working as it should.

On another note i think you don't need to set core_freq if you use enable_uart=1.

  • yes , i have disabled the bluetooth under the config.txt , done the enable_uart=1 successfully, and ran the systemctl disable hicuart , even though iam not able to see any data on the screen , the port is getting opened successfully , iam using gtkterminal to perform the operation
    – Rangith123
    Commented Jan 23, 2017 at 5:14
  • @Rangith123, check the baudrate maybe ...
    – Ephemeral
    Commented Sep 5, 2019 at 16:02
  • @Rangith123, also, you can use piscope tool for see the datas modulation on RX and TX pins in software side.
    – Ephemeral
    Commented Sep 5, 2019 at 16:09

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