I am controlling the RTS and DTR signal of an FTDI USB to Serial adapter using pyserial. I succeed doing so on two machines (Windows 10 and Ubuntu 18.04), but fail to do so on an older device using Ubuntu 14.04.
Either I cannot write without receiving an exception. Otherwise I suspect it could be another program accessing the said ttyUSB port. Therefore I restricted the access to ttyUSB to 600 using an udev rule.
Now, I need the python program to be executed with root access, but the behavior has not changed otherwise.
Some sum up:
- port is correct (it disappears when unplugging and vice versa)
- hardware works on other systems
- Changing DTR to true or false has no effect
- problem appears with pyserial on Ubuntu 14.04
I am running out of ideas. Do you have any idea how I could proceed?
