I'm trying to check if UART on my Orange PI is working. 

I've enabled UART via armbian-config and rebooted OPi.

 

root@orangepipc:~# dmesg|grep tty
[    0.000000] Kernel command line: root=UUID=e5185d19-ff08-47bb-8673-1779ef917d92 rootwait rootfstype=ext4 console=ttyS0,115200 console=tty1 hdmi.audio=EDID:0 disp.screen0_output_mode=1920x1080p60 panic=10 consoleblank=0 loglevel=1 ubootpart=530c2b83-01 ubootsource=mmc usb-storage.quirks=0x2537:0x1066:u,0x2537:0x1068:u   sunxi_ve_mem_reserve=0 sunxi_g2d_mem_reserve=0 sunxi_fb_mem_reserve=16 cgroup_enable=memory swapaccount=1
[    0.000189] console [tty1] enabled
[    1.975487] console [ttyS0] disabled
[    1.995636] 1c28000.serial: ttyS0 at MMIO 0x1c28000 (irq = 42, base_baud = 1500000) is a U6_16550A
[    1.995692] console [ttyS0] enabled
[    2.018619] 1c28400.serial: ttyS1 at MMIO 0x1c28400 (irq = 43, base_baud = 1500000) is a U6_16550A
[    4.800597] systemd[1]: Created slice system-serial\x2dgetty.slice.

 

Device file exists, but when I try to listen it  there is nothing  in output.

 

I tried simple test using cat and echo:

cat < /dev/ttyS1
echo "test" > /dev/ttyS1

 

as well as minicom and connected nodeMCU which sends a message every second towards UART.

Still nothing in /dev/ttyS1 output.

 

Please advise probably I do something wrong while checking UART?

 

9 hours ago, OlegEF said:

Please advise probably I do something wrong while checking UART?

Did you install loopback wire between pins 38 and 40 on the header which is where UART1 is located ? Otherwise, for pin 8 and 10, it is UART3 ...

Then, you can use "picocom -b 115200 /dev/ttyS1"