Products > Test Equipment
Unknown GPSDO but BG7TBL logo on the circuit board and OCXO !
Noy:
So same behaviour here.
Pin 1 sending 1pps.
GPS Module says:
--- Code: ---$GPTXT,01,01,02,u-blox ag - [url=http://www.u-blox.com]www.u-blox.com[/url]*50
$GPTXT,01,01,02,HW UBX-G70xx 00070000 FF7FFFFFo*69
$GPTXT,01,01,02,ROM CORE 1.00 (59842) Jun 27 2012 17:43:52*59
$GPTXT,01,01,02,PROTVER 14.00*1E
$GPTXT,01,01,02,ANTSUPERV=AC SD PDoS SR*20
$GPTXT,01,01,02,ANTSTATUS=DONTKNOW*33
$GPTXT,01,01,02,LLC FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFD*2C
$GPRMC,110520.40,V,,,,,,,151220,,,N*7B
$GPVTG,,,,,,,,,N*30
$GPGGA,110520.40,,,,,0,00,99.99,,,,,,*65
$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
$GPGSV,3,1,12,02,28,241,,04,01,087,,05,50,297,,06,08,200,*7D
$GPGSV,3,2,12,07,69,088,,09,36,086,,13,19,266,,14,06,158,*76
$GPGSV,3,3,12,16,09,025,,28,00,162,,29,00,309,,30,64,183,*76
$GPGLL,,,,,110520.40,V,N*49
$GPRMC,110521.00,V,,,,,,,151220,,,N*7E
$GPVTG,,,,,,,,,N*30
$GPGGA,110521.00,,,,,0,00,99.99,,,,,,*60
$GPGSA,A,1,,,,,,,,,,,,,99.99,99.99,99.99*30
$GPGSV,3,1,12,02,28,241,,04,01,087,,05,50,297,33,06,08,200,*7D
$GPGSV,3,2,12,07,69,088,20,09,36,086,27,13,19,266,26,14,06,158,24*73
$GPGSV,3,3,12,16,09,025,25,28,00,162,,29,00,309,,30,64,183,31*73
$GPGLL,,,,,110521.00,V,N*4C
$GPTXT,01,01,02,ANTSTATUS=INIT*25
--- End code ---
Regarding this:
https://portal.u-blox.com/s/question/0D52p00008HKCf6CAH/not-a-real-m8n-i-think
I think its a fake M7.
Would be interesting if a genuine one can output also 1pps at pin 1? :-D
Noy:
ARGHHHH...
Started to readout the Atmel but my usbasp was jumpered wrong.. I think 5V on nRST..
Now the ALM is permanent on and the ACT is off..
But i think the GPS Module and the Atmel is still working on the UART?
I read the think out now. Attached the HEX files.. Will order a new Atmel and hopefully the hex is correct and its working again than..
Edit: I think the readout is garbage...? But on the UART is still the same communication..
I think PortC is gone.. All LED and unfortunally also the ADC Pin? I'm unsure.
Now where can i get a proper hex file? I will order a new Atmel but then?
And my UART communication.
Noy:
Ok, it looks like the Atmel is not doing anything important?
I poked a bit around and found pin 2 is outputting 1.0000kHz and 13 is outputting 1.0003khz but it looks like these pins aren't going anywhere?
Maybe i will lift the Atmel up and look under him..
I think the Atmel is only configurating the GPS Module and then measuring the voltage at / under a specific voltage he is switching off the red LED?
And he is switching the green led but i don't know for what he is looking at, maybe some GPS Module message?
If so, i think there are 100k in series on the GPS TX pin or?
I mailed to BG7TBL and asked for a new Atmel / the binary file.. maybe they can help me. Could there be some other issues?
Regarding my counter it looks like its still functioning beside the LED signaling..
Edit:
One thing wha makes me curious.. The 5V i accidantly supplied to the Reset Pin has a 10k in series (USBASP self programming jumper mounted , other signals jumpered to 3.3V) so why could this destroy the Atmel?
If the Atmel is really only "houskeeping" and if don't get the binary / new Atmel i think i can rewrite the code. Config message is already collected..
I only need to know the specific "good" voltage border or?
Edit2:
One thin what makes me curious is the 5V i accidantly supplied to the RESET has 10k in series (USBASP self programming jumper, other signals were set to 3.3V with the other jumper). How could this destroy a Atmel?
Edit 3:
Working again, the series resistor from GPS TX-> Atmel was faulty probably from my solder connection to my LA..
Now ACT is flashing again (Atmel is looking for GPS Module messages..)
Now i have to check if the ALM Led is going off at any time. Currently Green is flashing, red is permanent on..
Edit 4:
Its working. everything is fine again. Found another broken / cracked cap and cleaned the whole pcb / resoldered some pins..
Now the ALM is not flashing any longer, its permanent on and if the 10MHz is locked and accurate it is permanent off..
So maybe my "fix" issues are also gone now. I think cleaning / resoldering was the clue.. Now i have a "good" GPS antenna on its way from china but no need anymore :-( :-D
Would be still interesting if an genuine NEO-M8N / M9N will output 1pps on safeboot_n but i don't think so. maybe a genuine M7N with the "reserved" pin.. which was the chip which was copied..?
thinkfat:
--- Quote from: TurboTom on December 14, 2020, 11:41:11 pm ---Yes, they somehow configured pin1 of the GPS module to output a 1PPS signal, see the attached photo. The LED D7 is flashing @ 1 Hz while D2 is flickering @ 1 kHz (just barely visible when quickly turning the head). Both these signals are routed via 18R resistors to the HC86 to the phase comparator (1 kHz) and pin 12 as where one of the XOR gates is used as an output buffer for the 1 Hz signal.
I also checked ublox datasheets and was surprised to find pin 1 more or less described as "reserved for future use"... Maybe the Chinese "copycats" have already entered the future while we're lacking behind... :o ;)
Btw -- my GPSDO is a rather early model, the date on the silkscreen says 2017-9-23.
P.S. Please disregard the flux mess at the SMA connector. It had been soldered in skew and I just couldn't leave it that way -- been too lazy to clean up afterwards ::)
Edit: Attached the GPS module config sequence with the data in hex format.
--- End quote ---
The footprint matches a Ublox NEO-M8 module (this one has a timepulse2 output on pin 1). The init sequence starts with 0xb5 0x62, looks like a UBX packet to me.
PS: ROM CORE 1.00 hints a NEO-7, also UBX-G70xx hints a 7-type core. But you're right, the footprint definitely is not a NEO-7 but rather a NEO-8.
PPS: the init sequence is a UBX-CFG-TP5 command that configures the timepulse:
--- Code: ----3.3773239E-07,B5,, header
1.1436623E-03,62,,
2.2876623E-03,06,, class 6 (CFG)
3.4316623E-03,31,, id 0x31 (TP5)
4.5756624E-03,20,, len=32 byte
5.7196624E-03,00,,
6.8636624E-03,00,, tpIdx=0, TIMEPULSE output
8.0076624E-03,01,, version=1, Message version 1
9.1516624E-03,00,, reserved
1.0295662E-02,00,, reserved
1.1439662E-02,32,, antCableDelay=50ns
1.2583662E-02,00,,
1.3727663E-02,00,, rfGroupDelay=0ns
1.4871663E-02,00,,
1.6015663E-02,E8,, freq=1000Hz
1.7159663E-02,03,,
1.8303663E-02,00,,
1.9447663E-02,00,,
2.0591663E-02,01,, freqIfLocked=1Hz (not used)
2.1735663E-02,00,,
2.2879663E-02,00,,
2.4023663E-02,00,,
2.5167663E-02,00,, pulseLenRatio=0x80000000 (2^-1, 50% duty cycle)
2.6311663E-02,00,,
2.7455663E-02,00,,
2.8599663E-02,80,,
2.9743663E-02,00,, pulseLenRatioLocked=0 (not used)
3.0887663E-02,00,,
3.2031663E-02,00,,
3.3175663E-02,00,,
3.4319663E-02,00,, userConfigDelay=0ns
3.5463663E-02,00,,
3.6607663E-02,00,,
3.7751663E-02,00,,
3.8895663E-02,EB,, flags=0xEB: active:1,lockGnssFreq:1,lockedOtherSet:0,
4.0039663E-02,00,, isFreq:1, isLength:0, alignToTow:1,
4.1183663E-02,00,, polarity:1, timeGrid:GPS
4.2327663E-02,00,,
4.3471663E-02,E1,,
4.4615663E-02,A7,,
--- End code ---
It configures the TIMEPULSE output to 1kHz, 50% duty cycle.
thinkfat:
--- Quote from: Noy on December 15, 2020, 01:15:37 pm ---ARGHHHH...
Started to readout the Atmel but my usbasp was jumpered wrong.. I think 5V on nRST..
Now the ALM is permanent on and the ACT is off..
But i think the GPS Module and the Atmel is still working on the UART?
I read the think out now. Attached the HEX files.. Will order a new Atmel and hopefully the hex is correct and its working again than..
Edit: I think the readout is garbage...? But on the UART is still the same communication..
I think PortC is gone.. All LED and unfortunally also the ADC Pin? I'm unsure.
Now where can i get a proper hex file? I will order a new Atmel but then?
And my UART communication.
--- End quote ---
The init sequence is similar, only it configures two timepulse outputs, one to output 1Hz, the other one to output 1000Hz. I guess that matches what you see on the pins of the module?
The module itself is quite a Frankenstein. It poses as a Ublox type "7", but the footprint is neither NEO-7 or NEO-8. Could be a clone (but why doesn't it have a Ublox label on it, then?), or a customer-specific module that was actually designed by Ublox. Could be excess stock that is being sold without label.
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