Ian replied to the topic 'Persistent Serial Port Mapping' in the forum. 9 months ago


It's strange on your machine it point to a gpio (which I thought is the gpio pins on the raspberry, but I might be wrong here)

I agree. Although further down the "parent chain" it seemed to get to an FTDI device the start to gpio looked very wrong.

Do a bit more searching and I found a site suggesting

KERNEL=="ttyUSB[0-9]*", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", ATTRS{bcdDevice}=="0400", SYMLINK+="gps_int"

and it was the KERNEL bit (rather than SUBSYSTEMS) that interested me so I tried

KERNEL=="ttyUSB[0-9]*", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", ATTRS{serial}=="A104E4YQ", MODE="0666", SYMLINK+="ttymount"

I don't understand this stuff so I'm just repeating bits of what others are suggesting and it looks like that seems to work - starting Ekos (with ttymount set as the serial port) seeks to not report issues and I can drive the mount (N/S/E/W - issues with everything "below the horizon" at the moment but GPS can't work indoors and still investigating cause ... but that's another issue).

If you/anybody thinks this wrong and wants me to try anything else I'm very happy to experiment further. I am getting a large number of timeout errors (but I think I got those on ttyUSB0 - but that's think so more playing around and experimenting and a separate issue).
On the assumption this is "the answer", is this thread enough to pass the info to others or does the tutorial need updating.