I offer you SIM300(D) hints and need help with GPRS comm

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srecko

Joined: 11 Oct 2007
Posts: 7
Location: Slovenia

01 Sep 2008 10:37 cms error 517

Hello, dear users of this forum. First, let me introduce myself.

My name is Srecko Lavric and people call me Lucky (=Srecko). My job is a teacher's assistant in electronic lab. Couple of years ago I started working on a project called Aqualink and we are close to starting a production. In this time I came across a lot of engineering problems and solutions too.

Currently I'm working around SIM300D GSM/GPRS module. The main benefit of this module is SMD variant. It can be easily soldered to the PCB without worrying about short circuits and bad solder joints. Also it has so big soldering pads, so you could solder some wires to it and use it on a breadbord.

Here are some important things, which might help someone to solve his problem, and maybe you will save an hour or two.

POWER SUPPLY

Powering GSM modules is very important, because they are very demanding peaces of equipment. Some of you didn't understand what is a transmitting burst. This is the borst of transmitting packets of data. This burst is present, when the module is registering to network, during voice call or when exchanging data in GPRS mode. During the burst the current spikes can be up to 2A, so your power supply must be capable of delivering this 2A during the peak power consumption.
Almost no regulator is capable of regulating the power supply in such manner, that the supply wouldn't fall a little during the burst. It is very important to keep this voltage difference as small as possible. It can be measured with an oscilloscope during a call. When starting a call the transmitter power is at maximum and is decreasing seconds later, when the cell acknowledges module that it can reduce power (in good signal conditions). The best would be digitizing oscilloscope, which can store the result for examination. In no case the voltage drop may exceed 350mV and the voltage may not fall under 3.5V. Please use 4V supply. Don't spare your capacitors. I use 2 capacitors 100uF/6.3V low ESR + 100uF tantalum + 1uF cheramic + 100nF cheramic. It works like a charm.

If your module powers off during TX burst, the power supply is the main reason. After this the module can not be auto restarted. It must be powered with PWRKEY. It is smart to monitor STATUS pin with your application. If it falls to logical 0, then the module is powered off. This pin needs 10k pulldown resistor to operate properly.

COMMUNICATION

Module's default baudrate is 115200bps. When the module powers up and registers the network, it releases an URC (unsolicited result code) "RDY". Newer software versions release "Call ready". Be careful of capital letters. This is issued at 115200.

If you don't want this communication speed (I don't know why not), then your application can issue "AT" command and wait for response. Try tis as long as you ger "AT" <CR> "OK" <CR>.

It is good to switch off the echoing of your commands. this is done with command "ATE0".

You can use only RX and TX pins to communicate with microcontroller, but you must keep in mind, that the length of what you receive can overflow your buffer and some data can be rewritten or truncated. I connected RTS and CTS together for this mode of operation.

Your firmare must be aware, that the module can send URC at any time. If you don't need this URC, you should at least cleas the RX buffer, if you are waiting for some other message.

SIM CARD

Very simple. Use 8 pin sim card holder with SIM presence switch. Connect all together as it must be (SIMCLK, SIMDTA, SIMRST, SIMVCC). Connect one end of SIM presence switch to GND directly, and other one to SIMPRE contact. This is all. If connected properly must work properly. Sometimes the contact on SIM holder or SIM card get dirty. They must be cleaned to work properly.

Another is "+CMS ERROR: 517". This means, that the SIM card is not ready. If you try listing the messages this may occure and sending will fail. You must pay attention to this error, since it can waste you a lot of time. For example, if sending an SMS message, this eror can occure. So better wait for SIM to get ready and then proceed. You can use AT+CMGL="ALL" for this and wait for "OK". Repeat this until you get rid of "+CMGS ERROR: 517".

MODULE RELIABILITY

This is only my oppinion. I used about 120 pcs of theese modules and all of them worked great without any problems and none of them died yet. They work fast and reliable. I'm more satesfied with SIM300D then wit SE (Wavecom) GS64.

I think this is enough for now. If you have any questions, please let me know. If you need some modules, I could offer you a peace or two.

If you have any experience with starting a GPRS communication between uC+SIM300D and UDP server, please give me a hint. I can't solve this puzzle yet. If you have any AT command example of what should be se up before usage of AT+CIPSEND, it will be highly appreciated.

If you came this far with reading, then thank you for your pacience and/or interest and best regards.

Srecko Lavric

P.S. I will publish this also in a new thread. Will se what will develope from this.

sabeti_1990

Joined: 16 Nov 2007
Posts: 178
Helped: 11

09 Sep 2008 9:58 +cms error: 517

hi srecko
your advice is very good & very complete I agree about that

be success Very Happy

freko

Joined: 25 Sep 2008
Posts: 6

25 Sep 2008 19:20 at+cipccfg

Hi Srecko, i developed an application with an AVR ATMEL, to read data trought serial port and send it to a Simcom300 and then send it to a server via GPRS, we have 20 of this devices working but in two places with low signal they stop working and we have to do a manual reset and then work again, i use a switched-mode power supply @ 1A but peaks of 3A, when the signal is low it need more power???

srecko

Joined: 11 Oct 2007
Posts: 7
Location: Slovenia

26 Sep 2008 7:06 gprs current spikes

Hello.

Yes, when the signal strength is low, the module uses more power. Also, when the module registers, it works at max power. When you are close to the base station and starting a call, the module works with max power, but after some time it receives the "feedback" from base station and adopts it's transmitting power to minimum possible. This way it saves battery.

You said, that you have done communication via GPRS successfully. Can you share any information with me? I'm interested in compleete step by step at commands and responses, to set up the module and start communicating. I mean for the first time, when the module is new and has nothing stored in the memory. Any help will be highly appreciated.

Hope to hear from you soon.

Best regards,
Srecko

movie_freak

Joined: 20 Mar 2007
Posts: 81
Helped: 2

27 Sep 2008 20:00 sim300 imei

http://www.edaboard.com/ftopic324930.html

hope this provides you some help

freko

Joined: 25 Sep 2008
Posts: 6

01 Oct 2008 1:10 change imei sim300

Sorry with the work i have no much free time, thank you for your answer, yes i developed an application to connect via GPRS to our server and send data, i am from Mexico (by the way sorry for my english, is not very good), with pleasure i post the detailed steps what i do to connect to my server, let me make a log and i post it, thank's again.

Added after 40 minutes:

Hi, is me again, this are the steps i follow to do the GPRS connection, i put the AT command follow by the desired answer:
AT //BEGINS AUTOBAUDING
OK

ATE0 //DISABLE ECHO
OK

AT&D1 //ENABLE DTR
OK

AT+CGSN //REQUEST IMEI
OK
111111111111111

AT+CMGF=1 //CONFIG SMS TO TEXT
OK

AT+CIPCSGP=1, "internet.itelcel.com", "webgprs", "webgprs2000" //SET APN, LOGIN, PASSWORD THE EXAMPLE IS WHAT I USE FOR MY CELLULAR COMPANY
OK

AT+CGDCONT=1, "IP", "internet.itelcel.com" //CONFIG MODEM TO POINT TO A IP VIA AN APN
OK

AT+CIPMODE=1 //CONFIG THE MODEM TO TRANSPARENT MODE
OK

AT+CIPCCFG=3,2,256,1 //SAVE CONTEXT
OK

AT+CIPSTART="TCP", "201.1.1.1", "6060" //BEGINS THE TCP CONNECTION TO A DESIRED IP AND PORT AND WAIT FOR THE WORD "CONNECT"
OK

CONNECT
/////HERE IS THE DATA TO BE TRANSMITED!!!

////WHEN THE MODEM SEND THE WORD "CONNECT" IS READY TO SEND ALL THE FOLLOW DATA TO THE SERVER, TO DISCONNECT CHANGE TO COMMAND MODE WITH
////THE "+++" COMMAND, OR IN MY CASE I USE THE DTR PIN TO CHANGE TO COMMAND MODE, IN THE DATASHEET IS EXPLAINED
OK
AT+CIPSHUT //CLOSE THE CONNECTION
OK

Best regards

maheshsutariya

Joined: 25 Sep 2008
Posts: 5
Location: India

13 Oct 2008 15:07 imei changer sim300

freko wrote:

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freko

Joined: 25 Sep 2008
Posts: 6

13 Oct 2008 19:35 what is difference between sim 300 and sim 340

Hi Maheshsutariya, of course i can help you, the sequence above is the sequence i use to connect the sim340 via GPRS to our server, we made acquisition of data with an ATMega324 and send it via the sim340 to our central server.

Silix

Joined: 26 Apr 2008
Posts: 9

21 Oct 2008 15:24 read gprs ip data simcom300

also try
www.utoolkit.com/gsmeval.php

is well described and the resources are provided

Blocks

Joined: 23 Oct 2008
Posts: 1

29 Nov 2008 0:55 sim340 imei change

Would anyone be willing to give advice on the antenna connection with the SMD variants of the SIM300/340? I know little about RF.

Samina Lee

Joined: 09 Sep 2008
Posts: 12

01 Dec 2008 3:20 atmel sim300

Hello,

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Sincerely
Samina
www.samway.net.cn

movie_freak

Joined: 20 Mar 2007
Posts: 81
Helped: 2

04 Sep 2009 19:22 imei change sim300

then u can only send data from the server to client when the client is connected to the server.. i.e. when the connection was initiated by the client and it is in connected state (it may be sending data or may not be sending data in this state ) at this state you can send data in both ways

yup ofcourse if there is any other method where in we can send data to a dynamic ip i would also like to know abt it.. but as far as i know this is not possible

Surya