Unable to use UART and Bluetooth in RPi3 with audio output simulatneously

Question

I am using Rpi 3b+ and I am trying to use the Bluetooth and UART simultaneously.

with ls -l /dev:

Serial 0 - ttyAMA0
Serial 1 - ttyS0

I had to use the UART (for reading coordinates in GPS) and meanwhile connect bluetooth and output the audio from the audio jack.

• Things I did:

  sudo systemctl stop [email protected]
  sudo systemctl disable [email protected]
  sudo systemctl stop [email protected]
  sudo systemctl disable [email protected]
  

• in config.txt:

  enable_uart = 1
  dtoverlay=miniuart-bt
  core_frequency=250
  

• in cmdline.txt:

  dwc_otg.lpm_enable=0 console=tty1 
  

My GPS code :

import serial
import time
import string
import pynmea2

while True:
    port="/dev/ttyAMA0"
    ser=serial.Serial(port, baudrate=9600, timeout=0.5)
    dataout = pynmea2.NMEAStreamReader()
    newdata=ser.readline()

    if newdata[0:6] == "$GPRMC":
        newmsg=pynmea2.parse(newdata)
        lat=newmsg.latitude
        lng=newmsg.longitude
        gps = "Latitude=" + str(lat) + "and Longitude=" + str(lng)
        print(gps)

The GPS data is coming, the bluetooth getting connected to phone but the audio is not okay. It is playing sometimes and then breaking.

Can I in any way swap the functionalities, so ttyAMA0 would be for bluetooth and ttyA0 would be for GPS communication?

AFTER REVERTING:

I got a new SD card, enabled only the serial intarface.

• ls -l /dev:

  Serial 0 - ttyS0
  Serial 1 - ttyAMA0
  

  UART and Bluetooth works fine.

Reverting changes in old SD card:

• I removed the dtoverlay=miniuart-bt and enable_uart = 1 again turned on serial through sudo raspi-config
• But ls -l /dev gives me only

  Serial 1 - ttyAMA0
  

  I am not able to find the /dev/serial0

Answer 1

If you didn't fiddle with things and enabled serial in raspi-config it should work using /dev/serial0 which will ALWAYS be the available serial port on GPIO 14/15.

What you claim to want is how it works if you don't break it.