Alas winter has hit the old homestead hard, with most of the family down with or recovering from variations of head, chest and other colds.
Hence not much fun stuff happening.....
However I did start thinking about how to get diagnostic info to a gps client program, and again came to the conclusion that it still might be better to read the gps stream myself as the other parsers generate errors without a fix present. So I modified my last software to add more diagnostic info to a file and took the GPS board for a walk. Within about 30 seconds a valid fix was reported and all seemed to be well, except that the LCD froze and didn't display the (expected) location information. Initially I thought this was my code doing something unexpected so I brought the unit indoors and plugged it into the monitor.
It turns out that a Python exception had occurred so the code was no longer executing. The exception was easy to fix but it highlighted that the LCD buffer continues to display what it was last sent and will continue to display that data even if the PI is shutdown. Therefore any code writing to it should have a high level exception handler and closing code to gracefully clear the display and power off the backlight. I'm new to Python and will need to think about how to do this elegantly and will try to incorporate this in the next version.