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Hi Henrik,

I've been doing some more reading regarding the NMEA string from the Rockwell datasheets. (19 pages in one 142 in other !)

I've discovered two choice bits.

(1.) The string is...

Hi Henrik,

Quite a bit to digest there. Good food for thought. Thanks.

I missed the fact that the custom characters for the medium digits was constantly loading in the loop. I've moved that...

Hi Darrel,

Hmmm, looking at the various timings I don't see how this can be done.

The NMEA string is output at the same point, the epoch of the PPS pulse, so the code is executing the string...

This is the full code with the Ints active but it's just updating first character.



;
; GPS NMEA Display code with GPSDO monitoring
;
; PIC16F876A ...

Redesign completed. New board made where all pins are accessible and pads for option of pullups/down resistors.

I have altered the software to use HSERIN and HSEROUT and all is well at the moment....

Hmm, guess which pins are not catered for on pcb ?

Redesign methinks. :D

That was it.

Using "DEC4 latsecs/lonsecs" in the gps string and changing to Word size variables uses the 4 decimal places.

Interestingly using battery power for the unit, I got exactly the same...

It's between DEC4 in gps string and Aint in locator code.

I can get the display right but not the locator using DEC4 in the gps string and DIGs in the display LCDOUT.

I can get the locator...

Now this is interesting.

If I mess with the size of any 'secs' variables it screws everything up. I can get Lat to 4 decimal places but not Long, it still goes to zero.

Right now I put the...

Hmmm no. I screwed that up somehow.

I realised it was saving DEC2 in the gps string so it would not be any different, so I changed it to DEC4 for now.

I changed the DEC2 in display line to...

Again you come to my aid Darrel. :D

I had limited the output by declaring the lat/lon secs as byte. Changed them to word and it becomes much more stable now. Datasheet says the decimal part is...

That was it Darrel. I had aliased the wrong variables to save renaming.

Gives correct code at 'back yard' 90% of time. Why 90% ? Well, it faces North and the number of satellites it will lock...

Hmmm, I've transferred the code over into my program but I must have done something wrong as the locator is incorrect.

I'm getting 10 and kd instead of 03 and kh which is correct at back of house....

Wow, wow and WOW. What can I say? That is your usual brilliant stuff.

I use DT_Ints, Big Digits, ADC Average and now your Locator code.

Many many thanks. I tried but just can't follow it...

Hi Andy,

That's the doc I took the info post from :)

Regarding working satellites, I downloaded a Maidenhead Locator App for my Android phone. Gives lots of other info too.
Able to get 10...

Hi Darrel,

Many thanks for this.

I wondered about the variables. I did have a try at following the code through in the hope I could perhaps work it out.

As a test. I changed the string to 8...

Darrel,

I found this regarding the 4th pair.

I have made a separate switchable sub for the Big Digit clock which just uses the h, m, s, part of the gps string called alone.

Pic of result. As near accurate to second as code allows.

7310

Surprisingly I do have it in asm if that helps. I think this is the applicable code after GPS string is parsed. Loc 1 to 8 are the Maidenhead.

I wanted it all in PBP so I could do what I wanted to...

Darrel,

Don't know if you are still reading this thread.

I wondered how difficult it would be to add the final two numerical digits of the locator so that it is the full 8 digit string.

I...

Complete working prototype system

7298

Rockwell GPS Module on right. PLL and TCXO board on left. TCXO is small vertical board top left. Small board at top with all wires is 7805 5v reg board....

Forgive me oh codemaster Darrel.

The idiot has been programming again. I am but a lowly code serf with an aged addled brain.......................................I forgot to declare the variables...

Darrel,

I tried incorporating your Month code but it causes odd errors in the ShowMonth, based on the FOR/NEXT loop and especially the idx. This is maybe where I placed it in the code but I will...

SOLVED. Wrong MPASM Suite.

I'm using PBP2.50 and at some point I must have upgraded the MPASM Suite to 8.90.
I needed to delete and re-install 8.15 instead.

I now get a complete compile and...

Hi Darrel,

Many thanks for your help.

The code I posted was the last working example on this PC connected to the net. The actual programming pc is in another room and not net connected...