sim900 module programming

Hello

I have Simcom sim900 GPRS module.

I have some pdfs but. I do not know where to start programming sim modules.

do I have to use a compiler ? like GCC or CCS C or Hi-Tech C ?

or how can I send AT commands to this sim module via serial port ?

and some of forums are saying that programming the modules and MCUs with a notebook doesnot give the correct result because of the power consumption of the module and MCUs. is that correct ?


thanks for answers .

search this forum.. i have answered this question many times.............

dear ckshivaram,

I searched but I couldnt find the right answer for my question. can you refer the page that you answered ?

thanks.

search for sim900 or 300 you eill get many post that i answered...

if you dont get then reply back with what you need excatly... test module with terminal and see how it works....

Hello

I can connect to sim900 module over serial port. I use SecureCRT. but sometimes I can connect, most of the times I can not. But all the time I see some letters on the screen when I restart the module.

if I adjust the session options as baudrate = 38400 and restart the module , i can see some letters like "şşşşÿÿÿÿ "

and if I adjust the baudrate =115200 and restart the module , i see these letters "IIIIÿşÿş" ....

but I can not send my AT commands to module. I cant write anything in the SecureCRT. even if Hyperterminal. I restarted the module many times but I could just send AT commands just two times. Once I could accomplish to send SMS to another phone. but now I cant.

why cant I connect to sim module via EVB everytime ?

keep changing the baud rate in the hyperterminal and give AT and see for what baud rate you get response as OK..

when you get response as ok do at&W and re power on and test it again if you get ok as response...

even if the given default baudrate is 115200 I get response at 38400. but not everytime. I just get answer to my AT commands and set baudrate as 115200 .and set it by AT&W .

I did it for this one but I do not know what to do for many others.after I finish the project I am planning to mass product for very huge quantity.

is there a shortcut to do this on sim module ?

you can ask the dealer to set it for required baus rate from the company itself....

is there a way to edit firmware ? and load it with flashloader ?

you can get the image from the company and flash but cannot modify it.

so I can understand that I should program the Microcontroller to make a TCP server on the GSM module via USART communication. ? or is there a way to embed the required codes to start tcp server service when powered on the GSM module ?

yes.. you need to create a seperate server which will have a unique IP address and this has to be accessed from your gprs modem whenever the program inside controller ( programmed by user, and interfaced to GPRS modem). you should program a controller that issues AT command to gprs modem to establish a connection with your remote server with unique IP address)

ckshivaram said:

yes.. you need to create a seperate server which will have a unique IP address and this has to be accessed from your gprs modem whenever the program inside controller ( programmed by user, and interfaced to GPRS modem). you should program a controller that issues AT command to gprs modem to establish a connection with your remote server with unique IP address)

Click to expand...

I think you miss understood what Ive said.May be because of my english I dont know.

I am asking for the TCP server service on GSM module.

the TCP service of the GSM module when I try to connect from my server (or client) interface to the GSM module to get the required strings which is read and sent via USART connection by microcontroller .

and My question is that ;

do I have a chance to embed the required codes into GSM module to open a TCP server session and listen to exact portfor incoming TCP (or UDP) requests. or should I sent the required AT commands from microcontroller everytime module powered on ?

PS : I am also writing the server software in VB.NEt which has a unique IP and listens to exacto ports for the connection requests coming from the GSM/GPRS module.

hello..

what ckshivaram is trying to say to you is that... your MCU should have some codes that will issue AT COMMANDS to the GSM MODULE in establishing GPRS..
example:
>> AT+CGATT=1 - Attach to GPRS Service
<< OK

>> AT+CGDCONT=1,"IP","wap.cingular" - Define PDP Context (cid, PDP type, APN)
<< OK

>> AT+CDNSCFG="208.67.222.222","208.67.220.220" - Configure Domain Name Server (primary DNS, secondary DNS)
<< OK

>> AT+CSTT="wap.cingular","wap@cingulargprs.com","cingular1" - Start Task & set APN, User ID, and password
<< OK

>> AT+CIICR - Bring up wireless connection with GPRS - THIS MAY TAKE A WHILE
<< OK

>> AT+CIFSR - Get Local IP address
<< 10.190.245.172 - returns IP address assigned to your module
<< OK

>> AT+CIPSTATUS - Get Connection Status
<< OK
<< STATE: IP STATUS - returns status of connection, needs to be 'IP STATUS' before you can connect to a server

this commands should be in your MCU... everytime your system is ON must send these commands..so that your GSM module will establish the GPRS connection..
i ave successfully done this in SIM300D..

now im going to ask you if you have successfully sent AT COMMANDS to SIM900D? does it reply good on every AT COMMAND?
if yes: pls tell me how did you do it? since all sim900D i bought doesn't seem to reply good..

thanks and more power....

hi homermike
my project is vehicle tracking ...getting latitudes & longitude from gprs extract taht information send it to gsm/gprs(sim900d)
& show the location on google map..
kindly tell me how iam going to send the lattitude & longitude to the module ?
if we use AT COMMAND WHICH U TOLD Above then where we have to use this?in hyperterminal ? if some wher else then in which language & wher have to do?
plzz help me out,thanks

1. u must have an MCU
2. connect the GPS module to the MCU
3. connect the GSM module sim900 to the MCU
4. MCU has only 1 UART port... then both of the GPS and GSM module is also UART... so u need to create a switching circuit either to chose which device u want to connect.. either GPS or GSM... we are using transstors on that for the switching
5. program ur MCU to connect first to GPS module... gather the coordinates, parse the longitude and latitude.... store it in a variable
6. then program ur MCU to connect to the GSM module... use AT commands to SEND SMS (AT+CMGS) in the message body u include the coordinate variables u just acquired from the GPS module...

but before all this... of course u must have a power supply for all the cmpnnts...
if you want to mass produce this project... let us be... we have already created this one.. and start producing also... we have also created a software on this where it displays live map or live location of the vehicle...

www.youtube.com/watch?v=49ospgcNT2E
watch that vid...

Thanx for ur reply...

MCU has only 1 UART port... then both of the GPS and GSM module is also UART... so u need to create a switching circuit either to chose which device u want to connect.. either GPS or GSM... we are using transstors on that for the switching

As we are using Atmega128 in which we are having a facility of two UARTs so is this possible for us to receive and transmit data simultaneously..

Secondly, can you kindly give us an idea that how to send AT commands in AVR programming??

romana naseer said:

Thanx for ur reply...

MCU has only 1 UART port... then both of the GPS and GSM module is also UART... so u need to create a switching circuit either to chose which device u want to connect.. either GPS or GSM... we are using transstors on that for the switching

As we are using Atmega128 in which we are having a facility of two UARTs so is this possible for us to receive and transmit data simultaneously..

Secondly, can you kindly give us an idea that how to send AT commands in AVR programming??

Click to expand...

Sorry, don't have any experience yet in AVR programming... and its good that ur MCU has 2 UART ports so no problem on switching the 2 modules...

AOA
our sir told us to make an application for loading a google map .. so u plz tell me in which language am i going to make this in "vb"or"php" & for these we need a online server ..help me out from this situation ...so which language iam going to choose?

u can use either VB.NET or VB.6.... u must integrate with GOOGLE MAP using GOOGLE MAP API....
and u need also a GSM MODULE connected to ur computer/server with a designated COM PORT so that u can get the SMS from the vehicle's device and plot it to the map..