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Eloclegin
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Joined: 01/07/2012
Location: United Kingdom
Posts: 25

Posted: 04:35am 26 Oct 2012

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Forgive me if this has been answered before on this forum... I am running both Duinomite Mini (DM) and MaxiMites (MM) for various DIY projects, using mostly MMBasic 3.2

I currently want to hook up an Olimex MOD-GSM onto a Maximite. The setup and code to talk to MOD-GSM all runs fine if MOD-GSM is hooked onto a DM. But if I use a Maximite I hit an immediate problem in that Maximite will not recognise OPEN "COM3:9600" AS #1. I have tried not specifying any bitrate. Still unrecognised on MM. There is presumably some issue with COM3 or COM4 on MM, which I have missed.

Can anyone advise? Anyway to get COM3 support? If not, is there a workaround, since I really want to run MOD-GSM on a MM.

Thanks in advance
Nigel

boss

Senior Member

Joined: 19/08/2011
Location: Canada
Posts: 268

Posted: 04:50am 26 Oct 2012

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Hi Nigel,

there is no COM3 on MaxiMite that's why.

Regards
boss

boss

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Joined: 19/08/2011
Location: Canada
Posts: 268

Posted: 04:56am 26 Oct 2012

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Hi,

try this:

https://www.sparkfun.com/products/9981

SPI to UART is little bit expensive but should work.

Eloclegin
Newbie

Joined: 01/07/2012
Location: United Kingdom
Posts: 25

Posted: 05:06am 26 Oct 2012

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Thanks Boss. Appreciate the v fast response.

1) Is there no other workaround to get MOD-GSM running. Eg different COM?

2) Ref, your alternative suggestion..can you give some more detail? I dont understand how COM works,so it would be helpful.

Sorry, I am a total newbie.....cheers

boss

Senior Member

Joined: 19/08/2011
Location: Canada
Posts: 268

Posted: 05:16am 26 Oct 2012

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Hi Nigel,

I'm not much proficient in GSM communication. Why you can't use COM1 or COM2 - that because of low bitreate speed(19200)? I have to have solve high speed UART for one of my project as well so your topic came in the right time.

Regards
boss

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6098

Posted: 02:25pm 26 Oct 2012

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I thing the MOD-GSM can autodect baud rate as low as 1200 so the Maximite COM1 or COM2 will be OK once you have the handshaking sorted out.

Jim

VK7JH
MMedit MMBasic Help

Eloclegin
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Joined: 01/07/2012
Location: United Kingdom
Posts: 25

Posted: 09:50pm 26 Oct 2012

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Thanks Jim. Any advice on how to sort the handshaking? I really have no experience in this area, and I guess it is just some simple protocol issue.

I try COM2:2400 and now the Maximite codes runs, but MOD-GSM does not respond.(at least it is a step forward). How would I modify the handshake from the MMBasic command anyway?

Olimex app note for MOD-GSM simple suggests. Eg to dial a call.
OPEN "COM3:9600" AS #1
PRINT #1, "ATD+(insert phone nmuber here);"

So I dont see much scope to vary handshake there? Do i need to do it in hardware? I see an Olimex errata that mentions that CTS must be held low, which I think I have done, Beyond that I dont understand the hardware protocol, nor what to do or try! I also dont understand how the MOD-GSM is being addressed, since this line of code )above) could surely equally be UEXT UART OPENing COM for a write to some other peripheral? Where is it defined to be MOD-GSM? Is it just assumed that MODGSM is the only peripheral hanging on the i/o bus, hence no need to address it? Perhaps I am confusing I2 bus and UEXT

Thanks for your patience with a total newbie!
Nigel

Eloclegin
Newbie

Joined: 01/07/2012
Location: United Kingdom
Posts: 25

Posted: 10:09pm 26 Oct 2012

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One more comment. My hardware setup. I am connecting an I2c bus of a MM (just wired GND, SCL, SDA). to the UEXT connector of MOD-GSM board.

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6098

Posted: 10:35pm 26 Oct 2012

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I don't have a MOD-GSM and only had a quick look at the specs.
I have assumed that it is standard serial and nothing to do with I2C
The handshaking is hardware so you are heading in the right direction with CTS low.
I would do the handshake lines with hard wired jumpers if you are using COM2 because it doesn't have any handshake lines.
COM1 does have handshake lines you can use.

Jim

VK7JH
MMedit MMBasic Help

Eloclegin
Newbie

Joined: 01/07/2012
Location: United Kingdom
Posts: 25

Posted: 11:13pm 26 Oct 2012

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Jim, i think my problem is that i am trying to get i2c on MM to talk to standard serial of the MODGSM, so doomed to fail. I need to go back and fundamentally revisit my whole hardware setup, or else try proper i2c to serial convertor. This was one of those moments where you try to throw together a very fast solution in minutes to get a project to send me SMS updates. I never properly thought it through. Thanks for your pointers. I am really impressed with how people like yourself dedicate time and patience to mere mortals like me, hole try to use these controllers half blind. All the best. Nigel

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