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Jun 25, 2008 10:03am
Img_missing_medium afritz 24 posts

I’ve been playing with my bug a bit and trying to get the GPS working. I could never get the unit to get a fix (at least according to the GPSLoggerSimpleGUI app). I tried both the internal antenna and later an antenna recommended in one of the threads (semons something or other).

I tried with and without the antenna with the "antenna active" flag in both positions. In all four cases the GPS had on the order of 15 minutes to get a lock before I gave up and went to the next combination.

I haven’t gone so far as to write my own app to provide more data about what is going on, because I feel like this app should work.

My questions:

1) What does the light on the GPS indicate. Some times it blinks (short, every couple of seconds). Some times it comes on for a period of time and goes off (like 5 or 6 seconds).

2) What does Active vs Passive antenna actually mean? I know one means internal and one mean external, but it isn’t clear to me which is which.

3) Should this "just work" or am I missing some steps?

4) My original GPS got RMAed because it wasn’t detected more than occasionally. Could I actually have a bad bug base? Has anyone else had similar experience?

Jun 25, 2008 4:54pm
Medium Bug Labs team finsprings 268 posts

afritz

1) What does the light on the GPS indicate. Some times it blinks (short, every couple of seconds). Some times it comes on for a period of time and goes off (like 5 or 6 seconds).

Mine goes green once it's gotten a fix.

afritz

2) What does Active vs Passive antenna actually mean? I know one means internal and one mean external, but it isn't clear to me which is which.

Active is the internal antenna, and passive is the external, at least according to the comments in IGPSModuleControl.

You can also navigate the front-panel menu to the GPS module and you will be able to see fix: True/False and IOX, which is the value of the IOX register:

* bit 0: GPS FIX Active Low.
* bit 1: Overcurrent condition caused by the active antenna path. Active Low.
* bit 2: Output to wake up device from sleep after push_to_fix. Active High.
* bit 3: Input to download firmware to flash.
* bit 4: Unused
* bit 5: Unused
* bit 7, 6: 0, 1 Passtive Antenna (External Antenna)
* 1, 0 Active Antenna (Internal Antenna)

So on internal antenna you should get 0x82 if you have a fix and 0x83 if not, and with the external it would show 0x42 or 0x43 (fix is active low).

I could never get a fix with the internal antenna, inside or outside. With that external antenna I was able to get a fix the first time in about 5 minutes or so, and a little quicker than that on subsequent tries.
Jun 25, 2008 5:10pm
Img_missing_medium afritz 24 posts

What does your light do when you don’t have a fix? Mine isn’t very consistent. I’ve only ever seen it blink orange and then not necessarily consistently. I’m wondering if don’t still have a hardware problem…

Jun 25, 2008 5:11pm
Medium Bug Labs team finsprings 268 posts

It flickers red IIRC

Jun 25, 2008 7:56pm
Medium Bug Labs team finsprings 268 posts

What does yours say under Modules\GPS\IOX in the LCD menu? Mine reads 0×43 when it has no fix using the external antenna (note that I corrected the IOX values in my previous reply because I forgot the over-current bit was active low and I got the 0×4x and 0×8x parts switched around because I apparently can’t add bits together in my head on Wednesday afternoons very well).

I watched it power up and there was one flash of the red LED at boot. Then, when the GPS module showed on the LCD it started to flash red every 4 seconds or so.

Jun 25, 2008 8:10pm
Medium Bug Labs team finsprings 268 posts

I just tried plugging in my GPS antenna, since I hadn’t tried it since I did the rootfs upgrade. I also installed my GPSConfig app as it gives you a simple LCD menu toggle for the antenna and defaults on boot to external.

I booted it with this setup and the LED went green in maybe 3 minutes.

Jun 25, 2008 8:13pm
Img_missing_medium afritz 24 posts

0×43 now. However, I got it to fix finally. I’m not sure what I did different, but after looking through the source code of the example and playing with it, I get a blinking green light.

I added some additional debug output and started paying attention to the concierge.log file once I got a green light an no position data on the position logging app. I’m wondering if it has been fixing before, but because I wasn’t paying attention to the light and nothing showed up in the log, I didn’t realize it…

The reason nothing is showing up in the position log is that I get an exception parsing the NMEA string from the position provider. This is no biggy as I already have code that does that. I can work around that problem without it being a major headache.

I actually prefer a event driven model where anyone who is interested in GPS info registers to find out about new fixes when they come in and I have code from another app the works that way that I’ll pull in.

Currently I’m writing a more robust GPS display app as a learning experience.

Thanks for the help. Sometimes asking the stupid question does yield fruit!

Jun 25, 2008 8:17pm
Medium Bug Labs team finsprings 268 posts

Glad you got it working. I had the same NMEA parse problem with GpsLoggerSimpleGui and my own GpsLogger apps, because the parse problem is down in one of the calls rather than in app code. I didn’t create a bugzilla ticket but I think John did.

IIRC, the call that triggers the problem is only in a System.out call, not in the one that actual creates the string that gets displayed.

Jun 26, 2008 6:33am
Medium Bug Labs team jconnolly 285 posts

afritz
0x43 now. However, I got it to fix finally. I'm not sure what I did different, but after looking through the source code of the example and playing with it, I get a blinking green light.


Sweet!

afritz

I added some additional debug output and started paying attention to the concierge.log file once I got a green light an no position data on the position logging app. I'm wondering if it has been fixing before, but because I wasn't paying attention to the light and nothing showed up in the log, I didn't realize it...


As a matter of fact, our web team has been leading an effort to implement a more collaborative model on buglabs.net/applications. I don't have a date yet, but you should soon have the ability to post your debugging App as a version of the old app. That'd be nice.

afritz

The reason nothing is showing up in the position log is that I get an exception parsing the NMEA string from the position provider. This is no biggy as I already have code that does that. I can work around that problem without it being a major headache.

I actually prefer a event driven model where anyone who is interested in GPS info registers to find out about new fixes when they come in and I have code from another app the works that way that I'll pull in.


The parsing exception is a known issue and we're looking to get it fixed for the next release. I definitely prefer the event driven model also, and it would follow the conventions we have for the other modules (BUGmotion comes to mind) in that regard. I'll have a look at the API, but I agree, that would be another nice feature in the upcoming R1.3 of the rootfs.

Additionally, you may find it helpful to circumvent the app-layer altogether and just

cat /dev/ttymxc/<slot no>

Where <slot no> is the slot number corresponding to the GPS module. 1,3 being the locations above and below the joystick, and 0,2 being directly above the hotkeys.


afritz

Currently I'm writing a more robust GPS display app as a learning experience.

Thanks for the help. Sometimes asking the stupid question does yield fruit!


Be sure to put it up on bugnet! 8) And feel free to drop into our IRC channel for any realtime help. [/url]
Dec 10, 2008 2:26pm
Img_missing_medium Sepu 3 posts

Our GPS isn’t working either, the number is:
0xa3
any help is appreciated, thx

Dec 13, 2008 10:02am
Medium Bug Labs team jconnolly 285 posts

Sepu
Our GPS isn't working either, the number is:
0xa3
any help is appreciated, thx


Sepu hopped into our IRC channel and it appears that he had not toggled the external antenna use to "on".
Dec 15, 2008 11:05am
Img_missing_medium Sepu 3 posts

jconnolly
[quote:521904baca="Sepu"]Our GPS isn't working either, the number is:
0xa3
any help is appreciated, thx


Sepu hopped into our IRC channel and it appears that he had not toggled the external antenna use to "on".[/quote:521904baca]
Still it changes form 0xa3 to 0x63, with one of the "unused" bits on.
Anyway the problem may be our location, Seems like GPS doesn't work properly here (Santiago, Chile)
Jan 4, 2009 9:16pm
Medium roland 11 posts

I have the same problem. No GPS fix is ever obtained (By the way, the only code that I could get working with my R1.3 bug is GPSRawFeedExample which shows identical output to cat /dev/ttymxc/2, GPSLogger 1.1, GPSLogger2 and GPSLoggerSimpleGui all die with a Java Exception)

External antenna plugged and on window sill where my other phones with GPS and GPS device (Nokia LD-4W GPS device and Nokia N95 and Nokia E71 phones) have no problem getting a fix.

My guess is that this is a low level software problem that will be fixed in R1.4 which fingers crossed will be out soon.

...Roland

Feb 11, 2009 2:52pm
Img_missing_medium nicobl 3 posts

Sepu
Still it changes form 0xa3 to 0x63, with one of the "unused" bits on.
Anyway the problem may be our location, Seems like GPS doesn't work properly here (Santiago, Chile)


The same problem here in Plano, Tx.
I can't imagine that our location is the problem. Other GPS devices work properly. Why does Sepu and I get those "cryptic" digets, while other get 0x43 or 0x83?

Maybe there is a problem with the firmware of the GPS module?
But I tested it with the gps-module and bugbase of my colleague and it works there neither. Any clue?

Nico
Feb 12, 2009 1:25pm
Img_missing_medium tannewt 2 posts

I get the 0xa3 and 0×63 codes but do get a fix with an external antenna. More info will be coming from the GPS in 1.4 (I think) so it should be easier to diagnose.