08 GPS and Filesystems

Rejuvenated from the midterm break, and my trip to Nice I dived right back into working on the Gumstix...almost. An exam on the first week back after the break scuppered that slightly, but our subsequent team meeting with Graham went pretty well in terms of discussing milestones, completed as well as upcoming, and this got me focused on the project again. Graham suggested a good plan of attack for getting at the GPS receiver that just hadn't occurred to me previously: bypass the gumstix and try talk to it through a normal unix/linux box. This way I'd be able to spot if connecting and communication was working smoothly with the proposed utilities, before porting them all onto the gumstix.

Unfortunately, I don't have Bluetooth on my laptop, but thankfully John does! Ironically though, John's laptop decided to bork itself the very minute we tried to start testing. Fortunately, it was only a minor breakage (in terms of things I needed working, anyway...) and we were able to test out gpsd and gpspipe in communicating with the GPS receiver.
As previously mentioned, the first step to this is to bind /dev/rfcomm1 to the MAC address of the GPS:

# rfcomm bind 1 00:0E:6D:5B:41:05

From here we merely need to start the gps daemon (gpsd) with rfcomm1 as an argument, and begin piping (gpspipe) the data being produced by the GPS receiver.

# gpsd -n /dev/rfcomm1
# gpspipe -r

Everything appeared to be working fully, with a stream of information being printed to screen from the GPS unit. We didn't try too hard in deciphering the data the GPS was providing as this wasn't the main goal of the exercise, and making sure that these functions work on the gumstix is a higher priority at the moment.


With this small victory in hand, I decided to try and finally flash the gumstix file-system. Firstly, I added any necessary extra packages to the buildroot and recompiled; no problems there, and the file-system was ready. I transferred this new file-system over serial, which took an absolute age, but seemed to be a safer option than flashing over, say, SSH.
When the file-system arrived it booted with no problem, for which I was rather glad. Then I realised that the wifistix activity light wasn't flashing; for some reason it just wasn't working. Figuring that I may have left out a package in the buildroot, I went back to the configuration section but unfortunately nothing jumped out at me. I did read on the gumstix wiki, however, that wifistix support is not automatically enabled in some of the older gumstix revisions - I suppose this is an excuse to get a newer revision with, hopefully, some problems ironed out.

Unfortunately, I stayed up quite late with the transferring of the new file-system (I think this may have taken close to an hour for a 3mb file), and slept in for a team meeting; oh dear...