GPS with PIC18F26J11 in FLOWCODE 7

[electron67]

Hello Matrix Forum

I am doing a project that uses GPS (NEO BLOX 6M) with Flowcode 6 works perfectly, I am using the PIC18F26J11, but this pic has no internal EEPROM; Then change the project to Flow 7, with an external EEPROM 24C16, the problem is that the Latitude is constantly changing from 25.xxxxx to 26.xxxxx without moving it and does not give me a reliable reading;

Could anyone help me !

Thanks
Enrique

[Benj]

Hello Enrique,

Please can you print the number of satellites to the LCD, this should hopefully help to gauge how accurate the information is. You can also use the IsDataValid macro to see if the data is accurate. Ideally the data needs to be accurate and the module needs to see as many satellites as possible to obtain an accurate position fix.

I don't think the v7 float routines are significantly different to the v6 routines so I don't think this should be the cause of the problem.

I've just moved to Windows 10 on a new PC and noticed that the time and date are no longer simulating. Is this just me or is it also not working for you?

[electron67]

Hello Benj,

I have window 7 and window 8, I will check the changes and I tell You, I keep you informed.
But the flowchart I use in Flow 6 works correctly and I import with Flow 7 without making any changes and only fails LATITUDE.

I will return the information.

Thank you
Enrique

[electron67]

Hi Benj

I include the data you recommended, the same flow chart in Flow 6 and Flow 7 in Window 7 and Window 8

Flow 6 Lat 25.784667 Long -100.244140 constant 16 satellites

Flow 7 Lat 25.xxxxx to 26.xxxxx Long -100.244140 Lat is changing 10 satellites

Apparently it does not work Latitude in Flowcode 7 vary distances of 10 to 50 Km

Thanks
Enrique

[Benj]

Hello,

Thanks for posting the files.

Out of interest what happens if you try increasing the size of the GPS receive buffer in v7 using the GPS component properties? You're currently only using 80 bytes to store the incoming data and you're only using 12.8% of the available RAM on your target device so there is certainly room for more.

It may be that v7 is taking slightly longer to process the incoming data which is leading to buffers getting full and leading to data corruption. A larger buffer may help to get around the problem though this is purely a guess.

If this doesn't help then let us know and I will double check the parser code is correct, though I beleive the same code is used for the simulation so it should be right.

[electron67]

Change it to 120 and 200 but the lcd display goes blank

[electron67]

Hi Benj

Change it now to 255 but the Latitude continues to vary constantly between 25.xxxxx and 26.xxxxx

Enrique

[electron67]

Hello Benj

I have been testing the circuit for a day with flowchart of Flow 6 and it works perfectly, it is stable and it detects when you move it, but I need the SERIAL EEPROM 24C16 component of Flowcode7

Enrique