Re: PBP and Lassen SQ GPS
hello
my objective is to get the 1PPS signal to synchronize a 10 Mhz VCXO
for the moment I spend hours to understand how to "speak" with this GPS Receiver
I got a lot of sotware .. TSIP104 seems the best one
for the moment the 1 PPS is a 0,5 PPS ! with a very short Positive pulse (0,2µS)
I have done a very big program to monitor it !
essai:
if PPS = 0 then goto essai
high ledrouge:pause 100: low ledrouge:pause 100
goto essai
I works ! but not very wonderfull, may be the 12F675 int clock has problem
to sample the 3,3 volts signal (1PPS from GPS) because the flashing is not OK all the time
I see in the GPS datasheet that PPS signal can be setted with many options
One could be good for me "option that say that PPS signal will be avalaible if the receiver
see at least 3 sats" I didn't find how to set up this condition
eitheir in NMEA or TSIP mode ..
If "somebody" has done with this PPS signal, any input will be appreciated
thanks
Francois
Re: PBP and Lassen SQ GPS
Re: PBP and Lassen SQ GPS
Hello
Yes I know .. also called 3DFIX
it is good to know if the GPS is in the 3D state
In my case the receiver is in 3D state with 5 sats "connected"
By the 1PPS is still "crazy" 0,5 PPS, I will try to play with interrupt to see waht append, but not so easy.
I have done a small app, LED is flashing to give the 3D state (1,2 or 3 flashes) it is enough ..
thanks for your input
Francois
Re: PBP and Lassen SQ GPS
Here is a link for someone that is doing something similar, with a PIC18F. It looks like they share the hex and assembly code. They do seem to do a pretty good job of explaining it in the two .pdfs
http://ve2zaz.net/GPS_Std/GPS_Std.htm