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Apr 03, 2013, 01:45 PM
Just another user
Dennis Frie's Avatar
Quote:
Originally Posted by Spejlo
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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Apr 03, 2013, 04:34 PM
Registered User
Quote:
Originally Posted by Spejlo
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?)?
Apr 04, 2013, 12:10 AM
Registered User
yes Neo-6M from HK.. I have 4 GPS units and only this one cause little problems
Apr 04, 2013, 07:02 AM
Registered User
Quote:
Originally Posted by Dennis Frie
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
Apr 04, 2013, 11:18 AM
Registered User
Quote:
Originally Posted by Spejlo
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?
Apr 04, 2013, 11:44 AM
Just another user
Dennis Frie's Avatar
Quote:
Originally Posted by Spejlo
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
Apr 04, 2013, 01:57 PM
Registered User
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
Apr 04, 2013, 02:03 PM
Registered User
Quote:
Originally Posted by msev
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
Apr 04, 2013, 03:45 PM
Registered User
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.
Apr 04, 2013, 04:56 PM
Just another user
Dennis Frie's Avatar
Quote:
Originally Posted by mbanzi
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.
Apr 04, 2013, 11:59 PM
Registered User
Quote:
Originally Posted by mbanzi
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)
Apr 05, 2013, 05:56 AM
Registered User
Quote:
Originally Posted by Spejlo
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?
Apr 05, 2013, 06:41 AM
Registered User
Quote:
Originally Posted by msev
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
Apr 05, 2013, 04:57 PM
Registered User
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.
Last edited by Devonboy; Apr 06, 2013 at 02:27 AM. Reason: typo
Apr 06, 2013, 05:23 PM
When in doubt, throttle out...
badlands's Avatar
Quote:
Originally Posted by Devonboy
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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