For 4MHz breadboard is OK - works for me all the time. Keep the connections short. Optionally, you can lift the pins of the microcontroller and solder the crystal directly onto them.
Actually it's the best option I know and it's not complicated at all.
You just need to plug the GPS and wait for the data bursts.
On some devices, you also have a 1 second output pin.
And you get a precision of about 1 ms... forever.
Well, that said, if you really want a 1ms precision, you have to count
the clocks of all the instructions you use and act accordingly, which is
a tricky task.
Dora.
pranam77 said:
GPS sysnchronisation is another option. But a bit complicated.