[time-nuts] Virgin time nutter fell at the first M12+ hurdle
azelio.boriani at screen.it
Wed Jun 11 14:33:27 EDT 2014
-the M12 uses positive TTL serial port logic: a MAX232 or equivalent
is the best you can use to connect the receiver to the PC with theWin
-the M12, by default, doesn't output nothing: use commands to get any
response (or use the WinOncore), no activity can be expected from an
unconnected, new M12+
-yes, if the PPS is regular then the receiver is working
-the M12+ can output NMEA sentences: just program it command @@Ci:
(see the manual to learn how to)
On Wed, Jun 11, 2014 at 7:50 PM, Chris Albertson
<albertson.chris at gmail.com> wrote:
> First off if you are getting PPS on the PPS pin the GPS is working. By
> default I don't think the MT12 outputs any serial data unless in response
> to a query. By default it is not a NEMA device.
> The protocol is binary so it would be rely hard to control it with a Window
> terminal program
> The simplest way to use the MT12 is to connect it to an NTP server. You
> may not want to run NTP, you want a GPSDO but NTP knows how to get the MT12
> running and NTP has a good log file that you can read to track what the GPS
> is doing. There are other software for controlling MT12 and other Oncore
> series GPSes that are better but NTP is already installed on many computers
> The other thing to watch with serial RS232 is the polarity. I'm pretty
> sure the MAX chip acts as an inverter. That might be good because RS232
> uses negative logic with a low voltage being a "one" and a higher voltage
> being a "zero" Well at least on the data pins, the control, I think is
> positive logic. If you get the polarity wrong it does not work
> On Wed, Jun 11, 2014 at 9:04 AM, Stephen <si at 2si.co.uk> wrote:
>> Hello everyone,
>> After reading quite a bit from your archives i've decided to try a put
>> together a 10MHz reference.
>> I've picked up a oncore M12+T GPS card and have tried to initialise it but
>> without any success thus far.
>> The user manual for the M12+T seems to suggest that i should be able to
>> hook the txd and rxd pins to a MAX3232 and be able to use the Winoncore
>> software to configure the card.
>> At power up the M12+T pins 1 & 2 are at 3V. After 10 seconds pin 2 sinks
>> to 0V, pin 1 idles at 3V and pin 4 give 1PPS. No serial output from the
>> card at all.
>> Anyone have experience of connecting an M12+T to rs232?
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> Chris Albertson
> Redondo Beach, California
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