Nice you got that working :-)
One note to the ttyAMA0. I mentioned earlier that you might see some additional traffic there. At least on ArchLinux that UART is used to dump out the dmesg log. Pretty annoying and it took me some time to a) figure out what's going on (for me it confirmed the UART decoder in my Rigol Scope works) and b) to silence that.
For me two things helped:
1. Get rid of the boot-messages by edit the cmdline.txt in /boot/ . Change the console=tty0 to console=tty1. Note: Removing the part from the command-line didn't work for me.
2. There is a
getty service running (could be an ArchLinux thing) which took me quite some time to really get rid of it as the service got restarted all the time. So in the end I edited the file
/usr/lib/systemd/system/getty@.service to use tty1 instead tty0 as well.
Some more infos that might be useful:
You should first check which /dev/tty* devices are actually there by use
ls /dev/tty* (and not all of them are physical devices). On my RasPi3 with ArchLinux I only see tty, tty0...63, ttyprintk (all of them are virtual devices) and ttyAMA0. So no ttyUSB (obviously no USB-UART connected) and also no ttyACM. After connecting an USB-UART (SiLabs CP210x) I also got the device /dev/ttyusb0 (lsusb shows in my case the USB device 4 is used). And the dmesg log had the entry
usb 1-1.2: cp210x converter now attached to ttyUSB0So maybe you should re-try using the USB part to see if it appears magically.
You can check the 'usable' tty device classes by
sudo cat /proc/tty/driversThe first column shows the driver, the second the 'class' like /ttyAMA or /tty/USB (no numbers), the third one the class number according to the
Kernel Doc. Any used drivers can be found in the /proc/tty/drivers/ subdirectory. You can read them (
sudo cat /proc/tty/driver/usbserial). But how much of use that brings