bg7tbl gpsdo master reference

[daddioo]

I include more photos, I couldn't upload them all on the previous page, I added a txt file with notes taken from the original display, sorry for the English I'm using Google Translate.
I correct an error in the txt file the R8 is not 0 it must be 10 ohm

[usagi]

There are now rubidium gpsdo on ebay from bg7tbl.

[daddioo]

The rubidium GPSDO is too expensive, I prefer with GPS controlled OCXO.
I need some help, last week I opened my GNSS GPS+BDS BG7TBL to replace the Trimble 72345 OCXO with Morion MV89, I mounted everything calmly, I moved the resistor on R4 for the 12V, then I closed the X2 contact for the DAC, then I connected the 12v and waited for about 2 hours without any Lock, I turned everything off and checked the pcb and I noticed that there was a drop of tin on some pins of the Mega 328PB, I managed to remove the drop of tin unfortunately it doesn't work anymore, I tried to put the Trimble back in it doesn't work anymore, the Mega 328 broke, I would be able to replace the mega 328, but I couldn't find the code in hex or anything else, I'm wondering if anyone has managed to read the Mega 328PB, should I throw it away or wait to find the file to upload. I forgot to write the hardware is GNSS-D-OCXO(RB), BG7TBL 2021-06-10.
Sorry for the English I'm using Google translator
Thanks to all
Giuseppe

[mvb]

The message was year ago... But I want share results of my research.
I've managed to connect display.
The protocol is HD44780 over semi SPI and can be handled by shift register.
The only problem, connector has only 3.3V pin and most of HD44780 compatible displays designed to operate with 5V.
HD44780 compatible with 3.3V logic but can't power LCD matrix correctly (see photo)
To solve this problem we need source of negative voltage (-0.7V in my case)
On the photos CR2032 battery connected as negative voltage source.
On scheme ICL7660 but this part not tested (waiting IC delivery)
---
Update:
The chematiic full tested.
The variable resistor is 10K. The resistor in backlight 220 Om, in my case.
If you have 3V display version (the small 8 pin chip mounted on display) ICL7660 doesn't need and upper contact of variable resistor not connected.
If you have ordinary 5V version of display use full schema.

[mvb]

The signals on display interface (6 pin) looks like on photos
The second one after shift register

[daddioo]

Hello everyone, today I made a mess, I used u-center to add another satellite, I added BeiDou then I had to save, instead of pressing save I pressed Revert to default receiver configuration, now I don't know how to configure it, I ask if anyone can help me if possible a configuration downloaded with U-center, my hardware is BG7TBL 2021-06-10, version that appears on the display is V20190126, if it is possible at least the configuration of TP5 (Timepulse 5). Thanks
 
Giuseppe

[daddioo]

The message was year ago... But I want share results of my research.
I've managed to connect display.
The protocol is HD44780 over semi SPI and can be handled by shift register.
The only problem, connector has only 3.3V pin and most of HD44780 compatible displays designed to operate with 5V.
HD44780 compatible with 3.3V logic but can't power LCD matrix correctly (see photo)
To solve this problem we need source of negative voltage (-0.7V in my case)
On the photos CR2032 battery connected as negative voltage source.
On scheme ICL7660 but this part not tested (waiting IC delivery)

Sorry, can you please provide the link where you purchased the GNSSDO Version 2024. Thanks
Giuseppe

[mvb]

This is not ordinary story....
This https://aliexpress.ru/store/5434135?spm=a2g2w.detail.0.0.41421c27p9TKnw&page=3 seller send me this device instead of FA2 frequency counter which I've bought.
GPSDO without display was not planed...
But it has display now

[daddioo]

This is not ordinary story....
This https://aliexpress.ru/store/5434135?spm=a2g2w.detail.0.0.41421c27p9TKnw&page=3 seller send me this device instead of FA2 frequency counter which I've bought.
GPSDO without display was not planed...
But it has display now

Ok, thanks for the reply, I will try Aliexpress if I am lucky.
Could you please verify the seller name, could it be TZT ?
Thanks
Giuseppe

[mvb]

yes

[daddioo]

Hello everyone, maybe someone can be interested in the original configuration of the Gps Neo M8N of the BG7TBL-V20210625, it was saved with u-center.
I am still looking for the version V20190126, I ask please if someone can help me, I am interested in at least the configuration of the TP5 (Time Pulse 5) or only the length of the pulse.
Thanks
Giuseppe

I found the configuration of V20190126 is the same as V20210625, only the GNSS changes with GPS and GLONASS

[Kurt_!]

Hello
Does anyone have software or a program for switching the display for this device?
 A simplification?
That would be great...

[32KCoreStore]

Hi,
Do you mean configuring the display to present a different format ie ppb, ppm, frequency error? Also changing UTC to whatever time zone you are in?

That is done by shorting two pins on the PCB before startup, then sending a config string into the GPSDO.
Kevin

[Kurt_!]

Yes, I know that. But it would be nice if it worked with some simple software.
Graphics software...