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    cf-28 gps very slow fix

    Discussion in 'Panasonic' started by Deregter, Jul 16, 2012.

  1. Deregter

    Deregter Notebook Geek

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    Hi,I have purchased a daughterboard with a FGPMMOPA6B 66ch gps receiver (datasheet here www.pvelectronics.co.uk/PA6B/PA6B.pdf) and installed it in cf-28 and enabled it in the bios. I know that the magnesium alloy may block the signal,so I ran some test with the case opened ImageShack® - Online Photo and Video Hosting and it was recognized by garmin mobile pc,igo8,gpsd etc but it was very very slow in acquiring the fix,more than 10 minutes!!! I checked the settings of windows' com4 port ImageShack® - Online Photo and Video Hosting and linux's /dev/ttyS3 (4800 bps 8N1) they should be good...Could it be an hardware problem?
    Please help! Thank you
     
    Deregter, Jul 16, 2012
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  2. mnementh

    mnementh Crusty Ol' TinkerDwagon

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    If it's a brand new install, the first lock will take a long time as the GPS builds its database of satellites. After the first lock, it should come much quicker. How many birds does it get, how's signal strength? Are you outdoors with a good clear view of the open sky and clear weather?

    I'm not familiar with the MediaTek MT3329 GPS chip; we recommend SiRF-III chipset-based GPS as they are a known quantity with very good results. Several of our members are experimenting with the newer SiRF-IV models, but I have no firsthand experience to pass along.

    Good luck and good hunting,

    mnem
    "I need some shells loaded with SiRF-IV satellite-shot and a 4,000,000 grain charge, please."
     
    mnementh, Jul 16, 2012
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  3. Deregter

    Deregter Notebook Geek

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    No,it's not the first time,the fix is always so slow..yes I tested it outdoor open sky,it gets 9 birds but it's easy to lose the fix when moving the pc... I have uploaded some pictures and xgpsd log (some errors are recorded) here Download gps.zip
     
    Deregter, Jul 16, 2012
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  4. ohlip

    ohlip Toughbook Modder

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    Provide a back up (cmos)battery for Gps and it will fix your problem.

    ohlip
     
    ohlip, Jul 17, 2012
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  5. mnementh

    mnementh Crusty Ol' TinkerDwagon

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    The datasheet says it needs backup 3V at pin 4 for proper operation; I don't see a coin cell holder on it, so I'm gonna say Ohlip's right on there. It's probably losing information from its database as fast as it can write it due to that B/U voltage not being present.

    mnem
    Backed up. Against the wall.
     
    mnementh, Jul 18, 2012
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  6. Deregter

    Deregter Notebook Geek

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    As you can see in the photo ImageShack® - Online Photo and Video Hosting there's a philips MKT-HQ-370-PH capacitor connected to pin 1 (VCC) and pin 3 (GND) and there's a purple cable that connect pin 1 to pin 4 (VBACKUP). Should I remove that capacitor in order to add a 3V CR2032 battery?
     
    Deregter, Jul 18, 2012
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  7. mnementh

    mnementh Crusty Ol' TinkerDwagon

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    That's probably the only reason it works at all; no it will not do.

    Yes, remove the capacitor and the jumper wire; they're just a stop-gap to make it work without a battery. It doesn't do anything to keep the memory intact.

    Go to Radio Shack; get this and the CR2032 battery that goes with it: Catalog #270-009

    Connect B(+) to pin 4, B(-) to Pin 3 or pin 8.

    Try that; see how it works.

    mnem
    There will be a test.
     
    mnementh, Jul 18, 2012
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