I need to use the serial port in the 26-pin header of an Orange Pi Zero. For what I have read, I assume that it is /dev/ttyS3. Is that right?
I have followed the instructions of 7profy, and now ttyS3 shows in /dev/, but I can't get the port to work. But when I hook a serial-to-USB adapter to pins 6, 8 and 10, and try to communicate with it using minicom, nothing happens. I have double-checked the communications settings (both minicom and PuTTY are set to 9600,8,n,1) and the connections, and I have tested /dev/ttyS2 and /dev/ttyS1 just in case, but I have got no reply at all.
How can I verify the serial port is enabled and working? Are there any extra steps to enable /dev/ttyS3 on the Orange Pi Zero?
uname -a outputs the following:
Linux orangepizero 3.4.113-sun8i #10 SMP PREEMPT Thu Feb 23 19:55:00 CET 2017 armv7l GNU/Linux