Dear community,
I am experimenting with MangoPi board, running Armbian, trying to communicate with the CC2530 Zigbee board . To do so, I need an available UART port, the UART0 (/dev/ttyS0, pins 8 and 10) seems to be occupied by the console, but there should be two other UARTs according to the schematic.
Some info:
pi@nezha:~$ uname -a
Linux nezha 5.19.0-rc1-d1 #trunk Fri Jul 22 12:44:22 MSK 2022 riscv64 riscv64 riscv64 GNU/Linux
pi@nezha:~$ setserial -g /dev/ttyS*
/dev/ttyS0: Permission denied
/dev/ttyS2, UART: unknown, Port: 0x0000, IRQ: 0
/dev/ttyS3, UART: unknown, Port: 0x0000, IRQ: 0
/dev/ttyS4, UART: unknown, Port: 0x0000, IRQ: 0
/dev/ttyS5, UART: unknown, Port: 0x0000, IRQ: 0
pi@nezha:~$ dmesg|grep tty
[ 0.000000] Kernel command line: root=UUID=09392a76-5b44-4ed0-b8c1-ea71be0c5a91 console=ttyS0,115200n8 cons ole=tty0 earlycon=sbi cma=96M rootflags=data=writeback rw no_console_suspend consoleblank=0 fsck.fix=yes fsck. repair=yes net.ifnames=0 bootsplash.bootfile=bootsplash.armbian
[ 0.022550] printk: console [tty0] enabled
[ 0.036087] printk: console [tty0] printing thread started
[ 2.054357] printk: console [ttyS0] disabled
[ 2.074657] 2500000.serial: ttyS0 at MMIO 0x2500000 (irq = 207, base_baud = 1500000) is a 16550A
[ 2.074952] printk: console [ttyS0] enabled
[ 2.097185] 2500400.serial: ttyS1 at MMIO 0x2500400 (irq = 208, base_baud = 1500000) is a 16550A
[ 2.097219] printk: console [ttyS0] printing thread started
[ 2.121099] serial serial0: tty port ttyS1 registered
[ 12.144928] systemd[1]: Created slice Slice /system/serial-getty.
[ 18.309394] systemd[1]: Found device /dev/ttyS0.
pi@nezha:~$ ls -l /boot
total 36312
-rwxr-xr-x 1 root root 64 Dec 23 21:18 armbianEnv.txt
-rwxr-xr-x 1 root root 38518 Jul 22 10:21 boot.bmp
-rwxr-xr-x 1 root root 173018 Jul 22 09:44 config-5.19.0-rc1-d1
drwxr-xr-x 3 root root 4096 Jul 22 10:20 dtb
drwxr-xr-x 2 root root 4096 Jul 22 10:19 extlinux
-rwxr-xr-x 1 root root 8399919 Jul 22 09:44 Image
-rwxr-xr-x 1 root root 5087353 Jul 22 09:44 System.map-5.19.0-rc1-d1
-rwxr-xr-x 1 root root 15056913 Jul 22 10:24 uInitrd
-rwxr-xr-x 1 root root 8399919 Jul 22 09:44 vmlinuz-5.19.0-rc1-d1
The usual approach seems to be using the armbian-config utlity, unfortunately, the utility does not allow configuring the hardware in the system branch. How do I enable the UART1? I tried to create the /boot/armbianEnv.txt file as follows:
pi@nezha:~$ cat /boot/armbianEnv.txt
overlays=uart1
and the ttyS1 seems to be created (?) but nothing to be seen in /dev/ttyS*
pi@nezha:~$ dmesg|grep ttyS1
[ 2.097185] 2500400.serial: ttyS1 at MMIO 0x2500400 (irq = 208, base_baud = 1500000) is a 16550A
[ 2.121099] serial serial0: tty port ttyS1 registered
pi@nezha:~$ ls -l /dev/ttyS*
crw--w---- 1 root tty 4, 64 Dec 23 21:18 /dev/ttyS0
crw-rw---- 1 root dialout 4, 66 Dec 23 21:18 /dev/ttyS2
crw-rw---- 1 root dialout 4, 67 Dec 23 21:18 /dev/ttyS3
crw-rw---- 1 root dialout 4, 68 Dec 23 21:18 /dev/ttyS4
crw-rw---- 1 root dialout 4, 69 Dec 23 21:18 /dev/ttyS5
Can somebody help please?
In ideal case, I’d like to swap UART0 and UART1 to get my RX/TX on pins 8 and 10, but enabling UART1 will make me happy as well 
Thank you, JP