I've been struggling to get my RPi4 serial working over pins 8,10.
I have both a Raspberry OS image and an Ubuntu 18.04 image for the RPi4. In either case, when I use RASPI-CONFIG to disable console and enable uart, I'm still unable to use minicom to see characters or to receive data over serial.
dmesg | grep tty console [tty1] enabled serial: ttyAMA0 at MMIO is a PL011 rev2 serial: ttySo at MMIO is a 16550
ls -l /dev/serial* /dev/serial0 -> ttyS0 /dev/serial1 -> ttyAMA0
setserial -g /dev/tty* /dev/ttyAMA0, UART undefined, Port: 0x0000, IRQ: 19 /dev/ttyS0, UART: 16550, Port 0x0000, IRQ: 21
sudo minicom -o -D /dev/serial0 or 1 no characters reflected back with loopback in place
enable_uart=1 is in config.txt
I'm getting the exact same results on both Ubuntu 18.04 and Raspberry OS. Neither enables the serial port to work. What else could I try or am I missing?