Hello again.
devterm a06.
Take a look in /dev
, there are multiple UARTs:
- ttyACM0
- ttyS1
- ttyS2
- ttyS3
- ttyS4
- ttyS5
- ttyS6
- ttyS7
Multiple questions:
- How do I identify on schematic which uart is on which pins?
(so far ttyACM0 is on the keyboard, and I think ttyS2 is the micro usb j7 on the ext board?) - Which of these are already used for something in the system and which are free for me to use by accessing the GPIO pins?
- does any of the UARTs have not only TX and RX pins but also RTS and CTS?
alternatively, can I configure any of the GPIO pins to be RTS and CTS?
Unfortunately applications → settings → armbian config → system → dtc (device tree) only opens empty file editor.
How do I read / understand / edit the device tree? - ttyS1-7 give input-output errors when trying to read or write.
ttyS2 additionally is only accessible by root.
Why so? how to make work? - Why the GPIO pins on mainboard on such unfriendly connector J3?
what is the best way to access the pins? - Isn’t it strange that a device with ‘term’ in its name does not have any serial port available from outside?