[ntp:questions] How to debug GPS PPS?

David Lord snews at lordynet.org
Mon Feb 15 11:32:24 UTC 2010


xyz-2041 wrote:
> On Feb 14, 4:58 pm, David Lord <sn... at lordynet.org> wrote:
>> xyz-2041 wrote:
>>> Thanks for your responses, guys.  Will reply in the future.
>>> Tried Garmin software to try to talk to the unit on a
>>> Windows box:
>>>    <https://buy.garmin.com/shop/store/downloadsUpdates.jsp?
>>> product=010-00124-00&cID=170&pID=70>
>>> None of these 3 programs worked.
>>> Tried MS Hyperterminal.  No good.
>>> Tried RealTerm (<http://realterm.sourceforge.net/>).  Got to see
>>> the messages once I got it working at 4800.  RealTerm shows
>>> the dataflow just like a breakout box.  Saw that it is *not* sending
>>> PPS on pin 1.  Just sending messages on pin 2.
>> What sentences is it sending NMEA or binary?
>>
>> How do you have the unit wired to the serial port?
>> The JST has pins 1-12 1=TxD2 2=RxD2 3=PPS 4=TxD1 5=TxD2
>> 6=PD 7=AuxBat 8=GND 9/10=3.6 to 6V 11=nc 12=NMEA-out(cmos)
>>
>> You need to check on below, it's best I can work out
>>
>> ie JSTpin      D9pin
>>       3 --------- 1
>>       4 --------- 2
>>       5 --------- 3
>>       8 ---+----- 5
>>            |
>>            +---- 0V
>>      10 -------- +3.6 to +6V
>>
>> CMOS generated RS232 levels should be ok but depends on
>> serial port of your pc. PPS out to DCD is given as 700mVp-p
>> into 50r so will need converting to rs232.
>>
>>> Tried to send  a message to change to 9600, and turn PPS on.
>>> Ignored messages because of improper syntax.  Needs
>>> proper checksum.
>> I have a gwbasic program for working out required messages.
>> GPSD will do it for you. Garmin site also have a windows
>> utility for generating required commands with checksum.
>>
>>
>>
>>> Does anyone know of software that actually works with this
>>> unit?
>> GPSD?
>>
>> David
> 
> 
> Changed back to the Oncore:
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> # GPS Oncore driver
> # server 127.127.30.0  prefer
> server 127.127.30.0
> fudge  127.127.30.0   refid GPSo
> 
> # PPS driver:
> server 127.127.22.0   prefer
> fudge  127.127.22.0   refid PPS
> 
> # Generic NMEA GPS Receiver:
> # server 127.127.20.0
> # fudge  127.127.20.0   time1 0.752 refid NMEA
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Pin 1 = PPS                       (Light is blinking once per second
> for about 200 ms)
> Pin 2 = Data: GPS -> PC    (Light blinks once per second--after pin 1--
> for about 300-400 ms)
> Pin 3 = Data: PC   -> GPS
> Pin 5 = Ground
> 
> 
> Installed:
> 
>  pkg_info | grep gpsd
> gpsd-2.90           Daemon that monitors one or more GPSes attached to
> a host c
> 
> 
> # ls -lta /dev | grep cua
> crw-rw----   1 uucp      dialer      0,  41 Feb 15 00:33 cuad0
> lrwxr-xr-x   1 root      wheel            5 Feb 14 15:42 gps0 -> cuad0
> lrwxr-xr-x   1 root      wheel            5 Feb 14 15:42 oncore.pps.0 -
>> cuad0
> lrwxr-xr-x   1 root      wheel            5 Feb 14 15:42 oncore.serial.
> 0 -> cuad0
> lrwxr-xr-x   1 root      wheel            5 Feb 14 15:42 pps0 -> cuad0
> lrwxr-xr-x   1 root      wheel            5 Feb 14 15:42 refclock-0 ->
> cuad0
> crw-rw----   1 uucp      dialer      0,  42 Feb 14 15:42 cuad0.init
> crw-rw----   1 uucp      dialer      0,  43 Feb 14 15:42 cuad0.lock
> 
> 
> gpsd outputs nothing at all:
> 
> # /usr/local/sbin/gpsd /dev/cuad0
> #
> 
> 
> # /usr/local/bin/gpscat -s 9600N1 /dev/cuad0
> 
> Get some HEX output once per second:
> 
> \x08'\xa2\x03\x08#\xa2\x06\x00\x00 \x08\x081\xa2\x17\x00\x00\x00\x1c
> \x00\x00\x00\x08*
> @@Ea\x02\x0f\x07\xda\x004+\x00\x02\xea\xb1\x08\xce,\xbf\xec>
> \x0f0\x00\x00N\xb3\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01
> 
>      remote           refid      st t when poll reach   delay
> offset  jitter
> ==============================================================================
> ...
>  GPS_ONCORE(0)   .GPSo.           0 l    -   16    0    0.000
> 0.000   0.001
>  PPS(0)          .PPS.            0 l    -   64    0    0.000
> 0.000   0.001
> 
> How can it be getting data on the serial port but NTP
> can't seem to see it?

Wrong baud rate and/or Oncore set to a config that
gpsd doesn't support?

If it still works from Windows is it possible to reset
to defaults that are supported by gpsd or NMEA drivers.


David




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