- WP8548 FX30S
- The system has no IP network connection (SMS only)
- The FX30S RTC is reset following POR (no battery is fitted to the FX30s)
- A SIM was fitted during testing - the system time is correct at the start of testing - I think this is because it’s being set by cellular network time
- I noticed that if I leave the SIM out the system time is not set even if the GNSS has time - I haven’t checked the impact on TTFF
I have noticed that in order to acheive fast time to first fix (TTFF) I need to issue a command line “poweroff” to the modem.
Is this because “poweroff” triggers long term storage of the alamanac and / or ephemeris? or something else?
Is there another way to trigger this other than “poweroff” ?
Is documentation available for this behaviour and how to acheive good TTFF performance with the FX30S?
Some test results
After power on reset TTFF start = 812 s After "gnss restart cold" TTFF start = 183 sec TTFF start = 256 sec After gnss fix and reboot from command line (no POR) TTFF start = 11 sec Following "poweroff" command and power cycle TTFF start = 34 sec TTFF start = 10 sec Following "poweroff" command and after 24 hours powered down TTFF start = 39 sec