[time-nuts] Connecting my Oncores
matt at smiffytech.com
Tue Apr 1 22:32:50 EDT 2008
Now that I've got a computer ready to be a time server, I am now
fiddling about with my GPS modules, checking that they are working and
As I have yet to build and interface board for my Trimbles (requires a
very fine pitch IDC connector, which is on backorder), I am testing my
Oncores, for which I have an interface box that I got through eBay and
have hacked to pass the 1PPS signal to DCD (this was unconnected when I
I tried talking to all three units using minicom - a VP and to GT+s at
both 9600bps and 4800bps. The VP kept spouting binary stuff at me,
which seemed to make most sense at 9600bps. The GT+s wouldn't do a thing.
I then fired up Windows through VMware (quite surprised to see that it
found my USB to serial adapter), acquired a copy of VisualGPS and, after
changing the port speed, managed to get the VP initialised so that it is
now sending NMEA data, which I can now get via minicom under Linux.
What is puzzling me about the VP is why I was unable to get this working
myself. Through minicom, at both 9600bps and 4800bps, I typed @@Ci,
which the manual tells me should get the device into NMEA mode. Nothing
happened at all - didn't even get the characters echoing back at me.
Yet VisualGPS managed to do this OK.
One of the GT+s is being totally dumb - to start with, both were, one
has now initialised at 4800bps and is spewing NMEA data, but is not
registering any satellites or a position - does this just need to be
left to its own devices for a while? Don't really know what to do with
the other one; there is a rechargable lithium battery on it - it's
showing 1.75 Volts. Wonder whether I should unsolder this and try the
unit without it. Really wish there was SOMETHING on the boards - a
jumper or whatever - that would guarantee me a factory reset.
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