this seems extremely interesting, i find it strange there is not more response to this mail will FSO try to incoporate it?
On Sat, Mar 14, 2009 at 2:24 AM, mqy <[email protected]> wrote: > > U-BLOX GPS chip ANTRAIS 4 and above can run in several power modes: > 0: Continuous Tracking Mode, about 3.5 mA > 1: Fix Now -- sleep mode about 130 uA > > Fix Now mode can be enabled by ubx binary message CFG-RXM. Detailed > parameters are configured by CFG-FXN. > > One of the problem is how to activate (wake up) from sleep mode. I've read > several message lists discussing this issue, it seems no way to wake up > through serial port. > http://kerneltrap.org/mailarchive/openmoko-kernel/2009/1/22/4794494/thread > > I've tried make GPS chip goes into sleep mode several days ago, but can't > wakeup it. > Last night I found good references through google: > > 1. > http://www.u-blox.com/customersupport/gps.g3/ANTARIS_EvalKit_User_Guide(GPS.G3-EK-02003).pdf > "When waking up TIM-Lx with RxD1, RxD2 from sleep- or backup state send a > number (at least 8) of > 0xFF characters to wake up the serial communication module otherwise the > first bytes may get lost. To > request a position fix a position request message must be sent via serial > port after waking up the > ANTARIS GPS Receiver." > > 2. > http://www.mikrocontroller.net/attachment/36822/NL_60415_-_Datenblatt_u-blox_GPS_Module_24092007_481.pdf > 5.3.3 Change operation mode > > "Please add header with dummy data for any command when the GPS module is in > sleep mode. This is required for wake-up in sleep mode. The dummy data in > hexadecimal is “0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF”." > > I've test this with ubx binary protocol: > 1) enable FixNow (sleep mode) by CFG-RXM, configure CFG-FXN > 2) periodically poll NAV-POSLLH, NAV-VELNED, NAV-SVINFO. Before writing each > poll request, write > unsigned char array {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF, > 0xB5,0x62,0x02,0x40,0x00,0x00,0x42,0xC8}; > /* note: first line: dummy data, second line: RXM-POSREQ */ > then sleep 1 second; > 3) toggle between "Continuous Tracking Mode" and "FixNow mode" by call > CFG-RXM (if in FixNow mode, first write dummy data and RXM-POSREQ) > > With MON-SCHED, the average GPS CPU load in "Continuous Tracking Mode" is > about 35%, regardless of send_rate, max nav SVs, 2d/2d nav mode. No > performance test data for FixNow mode for now. > > > > -- > View this message in context: > http://n2.nabble.com/Good-news%3A-FixNow-mode-can-be-wakenup-through-serial-port-tp2476690p2476690.html > Sent from the Openmoko Community mailing list archive at Nabble.com. > > > _______________________________________________ > Openmoko community mailing list > [email protected] > http://lists.openmoko.org/mailman/listinfo/community > _______________________________________________ Openmoko community mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/community
