Noooo, GPS connection lost (GR-230)

GPSMike · Occasional Visitor Joined: Nov 26, 2003 Posts: 12

Hi everyone!

I was playing around in that SiRFdemo program with my Holux GR-230 and tried some settings. One of the things i wanted to check was the "Synchronize protocols..." settning. Well, now i seem to have lost connection to the device. :/ (i though atleast that i would be getting a popup window or something, but nooo.)

All I can do right now is tp connect to the unit through my USB dongle on my laptop without getting any GPS-data. I dont own the USB-DATA-cable around, which seems to be the one that makes it possible to change back to NMEA. So all i can do is to connect with the device, and try to make changes, but nothing seems to be helping.

Well, i bet this is all my own fault, but is there a way to fix this whitout having to send the unit back to holux?

Thanks for taking the time!

-Mike

Dave · Posted: Fri Dec 19, 2003 7:29 am Post subject:

There's only two ways of fixing this.

1) purchase the data cable and connect it to the PC with the cable and manually switch it back.

2) send it back to Holux who will do this for you.

GPSMike · Occasional Visitor Joined: Nov 26, 2003 Posts: 12

Hi!

Strange that Holux doesn't bundle the data-cable if they knew about this problem.
I'll contact the store where I bought my unit from and see if I can borrow or get a good price cut off the data-cable. Worst case scenario right now is that ill have to send the unit to UK and get a replacement, which could take a while (christmas, new year etc). Too bad because I only had it for 2-3 weeks...

Thanks alot for the quick reply!

-Mike
Sweden

GPSMike · Occasional Visitor Joined: Nov 26, 2003 Posts: 12

A extra question:

Has anyone modified the USB-Power cable to work as a DATA Cable? Is it even possible?

-Mike

Dave · Posted: Fri Dec 19, 2003 12:43 pm Post subject:

I'm sure it's possible but you would have to know the pin-out, and it's probably not worth the hassle in doing so.

GPSMike · Occasional Visitor Joined: Nov 26, 2003 Posts: 12

Woho! :D

I fixed it!

Ok, so how did i do?

While I was surfing around the net for a store holding the USB-DATA cable I noticed that Holux also has a serial-data cable... so I simply decided to make one my self. Smile

I used a usb extender cable (male/female), and a serial cable that I got from a old COM9 mouse. So all I did was to connect the RXD (Receive data) and TXD (Transmit data) to the right pins on the USB cable, and also the Ground and connected pin 7/8 togheter (RTS/CTS, Ready to send/Clear to send).

A small illustration:

Then I started up Sirfdemo.exe and changed back to NMEA 9600bps.

I'm just glad that I don't have to order a cable I most likely would use this one time, or to send my unit to UK to get it fixed (especially when I bought it so recently).

Thanks for having such a great page!

Over and out.

-Mike
Sweden

Dave · Posted: Fri Dec 19, 2003 5:02 pm Post subject:

Superb, it's good to know it's easily done! Thumbs Up

tc_discoz · Occasional Visitor Joined: Dec 21, 2003 Posts: 9

Sven, I have the same problem - I would like to try out your cable solution. But I wonder how you actually connect to your GPS receiver.
There is only a mini-USB (Type B) connector - your picture shows that you use a "big" type A USB connector.

Do you connect your cable with the USB charger cable that comes with the GR230 or how does it work ?

Many thanks,

TC

ChristophRD · Occasional Visitor Joined: Dec 20, 2003 Posts: 4

Hej tc_discoz,

he is using an usb-female type A connector.
I tried the same solution without any success at this time.
Rolling Eyes

As you can see on

http://www.gpware.com/PDF/Holux_Bluetooth_GPS_Receiver.pdf

on page 11 the USB Mini Type A connector is supplied with the serial interface. (RxD/TxD).

I tried to use a standard serial cable (D-SUB9) connected to an USB-Slot-connector with four wires:
1 TxD-RxD
2 RxD-TxD
3 GND-GND
4 connection between RTS/CTS (PINs 7&8)

SirfDEMOs Error-Log shows CE_BREAKs and CE_FRAMEs en masse.

Any hints?

Thanks a lot,
CHRIS.

ChristophRD · Occasional Visitor Joined: Dec 20, 2003 Posts: 4

Two corrections:

D-SUB9:
connections between pins seven and eight.
Eight and close brackets results in this smiley: 8)
Mr. Green

Mini USB Type B, not USB Mini Type A connector...

Regards,
CHRIS.

tc_discoz · Occasional Visitor Joined: Dec 21, 2003 Posts: 9

Chris, in theory you have to connect the pins as follows:

Mini USB Type B <=> SUB-D9
1 - 5 GND
3 - 3 TXD
4 - 2 RXD

Also you have to cross 7 and 8 of the Sub-D (RTS, CTS).

The only question that is still unanswered for me:
Where do you get the Mini USB Type B connector from ?
- Mike seems to use the USB-Type A connector which is the big one that doesn't fit into the BR 230.
- Chris, you use a USB slot which I suppose is also USB-Type A.

So how to get from USB type A to Mini USB type B ??

Any help is much appreciated !

TC

ChristophRD · Occasional Visitor Joined: Dec 20, 2003 Posts: 4

tc_discoz,

sorry- I've forgotten to mention that I am using the supplied USB-cable. Big type A to mini type B. I am using the USB-slot as an adaptor.

If you are successful, please give me a hint.
My connection is still not running...
:-(

USB-cable to RS232 DSUB9 in detail:
+5V red - not connected
RxD white - connected to RS232 - TxD (PIN2)
TxD green - connected to RS232 - RxD (PIN3)
GND black - connected to RS232 - GND (PIN5)

Anything wrong?
I am really angry about Holux.
This is not low budget!
Stop!

Regards,
CHRIS.

tc_discoz · Occasional Visitor Joined: Dec 21, 2003 Posts: 9

Chris, did you check whether the supplied cable is fully connected at all ?
I think that the supplied cable does not have the data wires, just Vcc and Gnd - thats problalby the reason you can charge but cannot initiate a USB connection.

I tested a cable that differs a little compared to yours:
RxD goes to RxD (Pin2)
TxD goes to TxD (Pin3)

Also I shorted pin 7/8 of SubD.

Still I cannot connect - also I'm not actually sure whether I have to connect @ 9600 or what.

Why did you choose RxD to Txd and vice versa ?

tc_discoz · Occasional Visitor Joined: Dec 21, 2003 Posts: 9

Btw, the red wire is 5V following USB-Standard.
But actually, the 5V pin connects to pin 1 of the Holux data connector, which is GND. So you have to connect the red wire to pin 5 of the SUb-D.

GPSMike · Occasional Visitor Joined: Nov 26, 2003 Posts: 12

Ok, some updates.

I did the most stupid thing the same day I posted my last message. I wanted to try if the last modified cable worked and did another "synchronize baudrate and profile" just to be sure my cable worked.
The result:
The lost connection to my precious GR230 was lost again (as planned). Then I reconnected it with my homemade cable to turn it back to NMEA 9600...
..BUT!
It didn't work...

So now I were back at square 1.
I tried all the diffirent combinations (RXD->TXD, RXD->RXD etc etc) without any luck. So somehow I had some increaduble luck when I got it to work the fist time. (who oh why must I keep screwing things up).

I invited over a good friend (which still has the electronic knowledge that i lost 1-2 years ago Smile

, and we examined the cable and the BT GPS, the connector and some COM9 sheets.
So this is the conclution:

The DATA+ and DATA- that the USB usually sends are NOT the same as RXD/TXD. The mini-USB connector on the Holux GR230 has a speciall usb type, which uses RXD and TXD instead of the standard DATA+/-.

But that shouldnt be a problem because the Serial port on the computer also uses RXD/TXD?

Theres another problem: the RXD/TXD from the computer communicates with signals using +12/-12V instead of +3,3-5V that the Holux GR230 await. So to get the voltage down you have to build a small circuit to get the voltage to the right level. If you do a small mistake at this point you risk frying your COM port on the computer. So I gave up at this point.

My guess is that the GR230 has a protector against higher voltage so it simply rejects the signals from the computer.

If you check the USB-DATA cable you see a small "box" in the middle of the cable. Our guess is that it contains components to change the RXD/TXD to DATA+/- (so that the usb port understands the signals) and to revers the signal outupts (a signal 1 from TXD is inverted to a 1 on the DATA+).

The Serial-DATA cable housing probably contains the components to regulate the voltage down to right levels.

Well, as I said before, I gave up and ordered the bloody cable. I thought that if i ever did some stupid setting-changes again ill always will be able to change it back again.

Hope this didn't cause much problems with your cablemaking at home. But as always: It's better to first research and try, than buy. Smile

-Mike
Sweden

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