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Old Apr 03, 2013, 01:45 PM
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Dennis Frie's Avatar
Denmark, Capital Region of Denmark, Naerum
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Quote:
Originally Posted by Spejlo View Post
hi Denis
I found one nasty bug.. some GPS receivers (ublox NEO 6) sends GGA and RMC together (no delay between)
everything is OK before homepos is set.. but after that.. all the calculations are little time consuming and GGA sentence is missing 2 chars (on baud 38400) (hope you understand my english

I fix it for myself (but it's not universal)

if (homepos==1) ggapos=3; else ggapos=5;
if (GPSbuffer[ggapos+1]=='A' && GPSbuffer[ggapos] =='G') {
Great to know, thanks a lot
It have never been a problem with the GPS-units I've tested, but I might consider to add a more flexible GPS-routine, that will not have this limitation.
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Old Apr 03, 2013, 04:34 PM
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Quote:
Originally Posted by Spejlo View Post
hi Denis
I found one nasty bug.. some GPS receivers (ublox NEO 6) sends GGA and RMC together (no delay between)
everything is OK before homepos is set.. but after that.. all the calculations are little time consuming and GGA sentence is missing 2 chars (on baud 38400) (hope you understand my english

I fix it for myself (but it's not universal)

if (homepos==1) ggapos=3; else ggapos=5;
if (GPSbuffer[ggapos+1]=='A' && GPSbuffer[ggapos] =='G') {
Which Neo-6 module are you using exactly? Is it Neo-6m (like rctimer,goodluckbuy,hk gps?)?
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Old Apr 04, 2013, 12:10 AM
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yes Neo-6M from HK.. I have 4 GPS units and only this one cause little problems
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Old Apr 04, 2013, 07:02 AM
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Originally Posted by Dennis Frie View Post
Great to know, thanks a lot
It have never been a problem with the GPS-units I've tested, but I might consider to add a more flexible GPS-routine, that will not have this limitation.
if I may suggest. move all calculations outside interrupt and everything should be OK
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Old Apr 04, 2013, 11:18 AM
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Originally Posted by Spejlo View Post
yes Neo-6M from HK.. I have 4 GPS units and only this one cause little problems
Just for information purpose which other gps's do you also have?
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Old Apr 04, 2013, 11:44 AM
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Dennis Frie's Avatar
Denmark, Capital Region of Denmark, Naerum
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Originally Posted by Spejlo View Post
if I may suggest. move all calculations outside interrupt and everything should be OK
Unfortunately, that will give some other complications. If the GPS-calculations are moved from the interrupt, the next serial-string will overwrite the previous string. I can make an extra receive-buffer, but it will require a bit of extra SRAM (and the GPS-calculations have to wait for the 10 and 5 Hz loop to finish, but that's most likely not a problem).

Nevertheless, this is probably the best solution. I just have to check the timing and re-arrange a bit
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Old Apr 04, 2013, 01:57 PM
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I think its only universal (bulletproof) way to move calculations outside of interrupt.
if I change baud rate to 115200 much more chars is missing

but if no one have this problem just take it easy.. no hurry.. I fix this for myself and maybe it's possible to add delay between RMC and GGA in ublox config
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Old Apr 04, 2013, 02:03 PM
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Originally Posted by msev View Post
Just for information purpose which other gps's do you also have?
EagleTree V4 10hz
HobbyKing G-OSD 1hz
and one unknown 1hz

all these have no problem
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Old Apr 04, 2013, 03:45 PM
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Is there a list of GPS modules that work well with the OSD (especially the 5-10Hz ones)? I am looking to upgrade my G-OSD 1Hz GPS to something better, not sure what to buy.

I've scanned through both the threads for the OSD and have seen several GPS models mentioned, but nothing specific mentioned.
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Old Apr 04, 2013, 04:56 PM
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Denmark, Capital Region of Denmark, Naerum
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Originally Posted by mbanzi View Post
Is there a list of GPS modules that work well with the OSD (especially the 5-10Hz ones)? I am looking to upgrade my G-OSD 1Hz GPS to something better, not sure what to buy.

I've scanned through both the threads for the OSD and have seen several GPS models mentioned, but nothing specific mentioned.
All GPS-modules with normal NMEA-strings should work. I use a MTK GPS, but it shouldn't be necessary to use that exact brand.

It's the first time I've heart of the problem mentioned by Spejlo, but I'll try to get that solved for next update.
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Old Apr 04, 2013, 11:59 PM
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Originally Posted by mbanzi View Post
Is there a list of GPS modules that work well with the OSD (especially the 5-10Hz ones)? I am looking to upgrade my G-OSD 1Hz GPS to something better, not sure what to buy.
I suggest NEO 6M.. it's clearly best I've seen.. it's fast (about 30sec to fix) and super sensitive (in two story building 6-7 sats)
don't be scared if this one doesn't work properly for now.. you can easily fix that (hard-coded but works like a charm)
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Old Apr 05, 2013, 05:56 AM
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Originally Posted by Spejlo View Post
I suggest NEO 6M.. it's clearly best I've seen.. it's fast (about 30sec to fix) and super sensitive (in two story building 6-7 sats)
don't be scared if this one doesn't work properly for now.. you can easily fix that (hard-coded but works like a charm)
Can you still configure the GPS regarding baudrate and frequency...For example in that case one could use both gps for flight controller and osd.. (that they would both use same value for baud rate and frequency)...What about UBX protocol?
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Old Apr 05, 2013, 06:41 AM
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Can you still configure the GPS regarding baudrate and frequency...For example in that case one could use both gps for flight controller and osd.. (that they would both use same value for baud rate and frequency)...What about UBX protocol?
I don't see any problem using one GPS for OSD and flight controller (I use it like this with ArduPlane 38400/10hz RMC and GGA)
UBX protocol was the first thing I've turned off. things that I have only one support UBX protocol.. NMEA is much more supported
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Old Apr 05, 2013, 04:57 PM
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Just got my first board built using Dennis' PCB v1.1 (and put the 47uF caps the correct way round).
Burnt bootloader, uploaded the graphics and default software.
Nothing out of the video, nada, zip.

It's late and I'm tired, probably doing something wrong...but, am I right in thinking the MAX7456 should output something to a monitor/screen regardless of any input (even without a camera connected or the Atmega running)?

Nigel.
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Last edited by Devonboy; Apr 06, 2013 at 02:27 AM. Reason: typo
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Old Apr 06, 2013, 05:23 PM
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Joined Mar 2010
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Originally Posted by Devonboy View Post
Just got my first board built using Dennis' PCB v1.1 (and put the 47uF caps the correct way round).
Burnt bootloader, uploaded the graphics and default software.
Nothing out of the video, nada, zip.

It's late and I'm tired, probably doing something wrong...but, am I right in thinking the MAX7456 should output something to a monitor/screen regardless of any input (even without a camera connected or the Atmega running)?

Nigel.
Nigel - yes you shoud get an output without a camera connected, sounds like your Atmega is running thou if you can firmware it?

Upload a clear picture of the PCB for the forum users to look at?
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