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Pr0f
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Joined: 09/12/2011
Location: United Kingdom
Posts: 10

Posted: 08:35am 09 Dec 2011

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Hi All,

Myself and a colleague at work have been experimenting with GPS and the Duinomite board, both of us are using different GPS modules, but the same Duinomite board (the one that has the outboard IO for VGA/KBD/SND)

Ok - so the plan was to use COM4 for the GPS using a protoshied to mount the GPS device, hence needing D0/D1 on the Arduino shield. My Proto board actually brings out the RX/TX and GND seperately as well.

We test the GPS and see the NMEA format packets (using USB to TTL serial)
We test the COM4 - with USB to TTL serial - nothing
Plug GPS into COM4 - nothing.

So a little bit more experimentation I see this:

I've used an LED via a 4K7 resistor, anode to +5V, cathode to the TX pin of GPS, and I see the LED blink off at 1s intervals - consistent with the GPS packets, but nothing received on COM4

I tried connecting the GPS to COM3 on the UEXT port - and voila - I've got GPS stuff coming in !

So there is something a little off with COM4 on these boards, which is UART5 on the PIC32 shared with 2 other digital lines. Is there a trick to getting these to work ?

My code (From the new user manual) is simple:

10 OPEN "COM4:9600" AS #4
20 PRINT INPUT$(1,#4);
30 GOTO 20

Changing line 10 to use COM3 and connecting the GPS onto the UEXT port - it works fine.

Any ideas?

Olimex
Senior Member

Joined: 02/10/2011
Location: Bulgaria
Posts: 226

Posted: 08:44am 09 Dec 2011

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I made experiments with our MOD-GPS and connected it with jumper wires to COM1, COM2, COM3, COM4 and all worked fine.

Please check your hardware, note that D0/D1 are also connected to RS232 driver and RS232 connector, if there is something connected to the RS232 connector the GPS output should be strong enough to fight the RS232 driver which output is weakened by R42 resistor 330 ohm.

Pr0f
Newbie

Joined: 09/12/2011
Location: United Kingdom
Posts: 10

Posted: 08:51am 09 Dec 2011

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Hi - thanks for replying.

These are the boards with no RS232 driver (not the mega board), it says that the UART pins are connected together with 2 digital lines via 0 ohm resistor links R2,R3 (looking at the board, there are 2 pads, no resistor, but there is a pcb track bridging them - and multimeter confirms they are connected).

As far as I can see, the only other connection on the circuit is the the other PIC pin ?

It works in COM3, so the module and code are ok - just not on COM4.

This is the board we are using:

http://www.olimex.com/dev/duinomite.html

Pr0f
Newbie

Joined: 09/12/2011
Location: United Kingdom
Posts: 10

Posted: 08:32am 10 Dec 2011

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I've now tested this on the other 2 COM port - the 2 'Maximite' style bit banged ports, and the GPS unit is working fine on those 2.

It's just COM4 doesn't want to play ball :(

As this COM port's pins are shared with other lines, do I have to do anything to set those lines into a state where they will not interfere ? It seems to me that setting both the lines that feed Arduino.DO and Arduino.D1 to input with no pullup should work - but tying this with the SETPIN command didn't work for me (using SETPIN 11,2 and SETPIN 12,2).

Any ideas guys ?

Firmware says 2.7, but there seems to be several '2.7' versions - how can I check the Duinomite has the latest f/w ?

I really do need to get this working, I plan on using the pins that COM1 / COM2 use for other functions, and will need both COM3 and COM4 for my project - a UAV controller.

Any help much appreciated....

Olimex
Senior Member

Joined: 02/10/2011
Location: Bulgaria
Posts: 226

Posted: 08:45am 10 Dec 2011

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please download latest beta firmware from http://www.kenseglerdesigns.com/cms/forums/
I don't know what is wrong with your board, all 4 COM ports work with my MOD-GPS I tested again after your post

Pr0f
Newbie

Joined: 09/12/2011
Location: United Kingdom
Posts: 10

Posted: 03:40pm 10 Dec 2011

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Downloaded the Dec 9th Firmware and it seems to have done the trick :)

Is there a firmware version string that can be PEEK'ed or a command to display the full version - if not, seems like that might be a worthwhile addition to the code.

Congratualations on an excellent board - I came across the Pinguino board first, which I am actually running STICK OS BASIC on (integer only), but was good to see the Duinomite evolve.

Thank you for you're assistance.

donmck

Guru

Joined: 09/06/2011
Location: Australia
Posts: 1313

Posted: 06:23pm 10 Dec 2011

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Pr0f said Downloaded the Dec 9th Firmware and it seems to have done the trick :)

Is there a firmware version string that can be PEEK'ed or a command to display the full version - if not, seems like that might be a worthwhile addition to the code.

Congratualations on an excellent board - I came across the Pinguino board first, which I am actually running STICK OS BASIC on (integer only), but was good to see the Duinomite evolve.

Thank you for you're assistance.

David,
Type "setup" without quotes, DuinoMite version can be seen up the top of the screen, along with the date is was produced.

By doing it this way, Geoff Graham's power up Copyright message is fully retained, and left unchanged.

Cheers Don...Edited by donmck 2011-12-12

https://www.dontronics.com

Pr0f
Newbie

Joined: 09/12/2011
Location: United Kingdom
Posts: 10

Posted: 06:57pm 10 Dec 2011

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Wow - that's another thing I've not seen before !

Thanks Don - will try that next time I plug the board in :)

Great forum by the way - I'll be posting up with some of my findings and hardware ideas hopefully not just questions for you guys ;)

David.

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