2021-04-02, 05:55 PM
PaddyB, thanks for spotting that. Although that was an issue, the main problem is that the ESP32 development board is configured as an Arduino, which must support a serial bootloader as well as standard run mode. For the RPI ttyUSB0 device, I had to write a utility that would toggle the RTS line while holding DTR low to force the board to run mode. For some reason, Windows must do this automatically when opening the COMx port, since the SK deltas happily streamed into TerraTerm without any RTS/DTR forcing.
With respect to the problem you pointed out, since my GNSS subsystem is now on this "Aux" device to the RPI, without timestamps being specified in the delta how does the PI ever get a time update? Normally my RPI boat computer is not connected to the internet, so it seems that without a GNSS timestamp, over time the RPI (and thus SK) will drift. I did play around with where to put "source" and "timestamp" in the JSON string, but couldn't get it to pass the data fiddler test.
With respect to the problem you pointed out, since my GNSS subsystem is now on this "Aux" device to the RPI, without timestamps being specified in the delta how does the PI ever get a time update? Normally my RPI boat computer is not connected to the internet, so it seems that without a GNSS timestamp, over time the RPI (and thus SK) will drift. I did play around with where to put "source" and "timestamp" in the JSON string, but couldn't get it to pass the data fiddler test.