Can some one help me. I have been throughout the forum and can't seem to find a direct detailed answer to my question.
I know there is an article with an option to connect a GPS module via "bypass" through the APM2 to connect to the u-center, however, I would like a direct connection to u-center.
Can I connect a GPS NEO-6m or LEA-6H module to my Win7 laptop's "Ublox u-Center" program via the USB connection, directly?
I believe I read somewhere that it can be done.
I am not worried about what actual physical cables to use, I'll make a custom one, I just need to know what wire assignment are to what connection to the laptop USB port?
I know the compass uses 3.3v but the GPS portion of the circuit works on 5v which is the computer's USB voltage.
On the GPS module we have the 4 pins; VCC, RXD, TXD, GND
VCC to 5v+(laptop USB port)
GND to USB Ground
and the other 2..... RXD and TXD I can try one combo and swap if needed. If I connected the voltage portion of the wires correctly, I imagine there is no risk in hardware damage to the computer or GPS module since those 2 other connections are only for data? Is this correct?
Will this work? Has anyone done this before?
Also a typical USB computer port has 5 connection "vias" doesn't it? 4 actual connection tracks and the USB casing which is ground, correct?
If so, I would have to play around with 3 connections to find which 2 will work for RXD and TXD?????
Replies
Oh, I forgot...RS232 serial ports use voltages which are incompatible with TTL devices. Data high is defined as (about) +12 V while data low is -12 V. A naked RS232 port is definitely contraindicated here!
Thanks Mike,
I just tried a direct connection to the computer just a few hours ago and it did not work, now that you explained data transfer rates of a usb port, now I know why.
I did, however try a USB to TTL and it did work, as far as establishing a connection.
It did actually connect to the U-Center with no problems but I have a problem that seems an enigma. It just doesn't make sense after everything I read. The transfer (save or load configuration) does not work.
As I am trying to load the 3DR-Ublox.txt to the GPS every command line times out and does not transfer successfully....even with a retry count of 10. (baud rate is set correctly at 38,400) When I try a basic "save configuration" same thing happens.
I followed the instructions as per Jabram that provides a lot of tutorials and videos over the forums, which was quite easy to follow and it makes sense, but it just does work for me.
Also tried different versions of U-Center.
It is like it can not communicate with U-center in that regard (saving or uploading) but in every other sense it works with the U-Center.
After debugging, I get all the graphs moving and can lock 12 satellites outside, etc.
My GPS LEA-6H and NEO-6M work but I want to be able to have full function; save, upload configurations etc.
Let me know how you make out......and if anyone had this problem and found the fix, please let me know.
Hi, Greg...
I'm going to try a direct connection as well; however, it will require a USB/FTDI converter. The GPS side of the system should be TTL (hi/lo logic or +5 V/0V) while the USB side will not obey those rules. The data transfer rates for USB are pretty high compared to serial standards. Even 115200 baud corresponds to less than 1 MB/s while USB 2.0 runs at 480 MB/s. Handshaking in the converter takes care of this problem. Converters are cheap, running about 3-7 dollars. VCC from the converter will go to VCC on the board, GND will go to GND. You should expect to swap TXD and RXD since both devices are "computers".
I have the necessary plugs on order, and expect to hook it up in 3 days or so. I'll let you know how it works.