gps and gsm with atmega 2560

[sravani.thatha]

now i have to receive the GPS RECEIVER data from the receiver and send it to an user mobile phone with the help of the GSM modem connected to the same controller with which GPS receiver is connected.

i could manage to work with GPS - ATMEGA2560 & GSM - ATMEGA2560 individually, but now simultaneously i have to work with GPS - GSM - ATMEGA2560. I have prepared RS232 cable so that at a time it can be connected to the controller,GPS,GSM. it is receiving data from GPS continuously but once it receives data for the first time it has to stop receiving data from GPS and start transmitting data to GSM in the form of command i.e.AT+CMGS="123456799";>message^z
and send this received data from GPS has to sent to user with mobile number 1234567899.

can anyone kindly help me in solving this problem. can i use RS232 in that form or is there any other choice of connecting those three (ATMEGA2560-GPS-GSM) at a time?

 

[ansarmytheen]

Dear friend,

you can conncet both device simultaneously by using soft uart and hard uart.

 

[sravani.thatha]

Dear friend,

you can conncet both device simultaneously by using soft uart and hard uart.

how can we implement this method???

 

[ansarmytheen]

Dear friend,

Which language you use?

I think you have already use hard uart.

In soft uart take two pin ,one for reception and other for transmission.

 

[sravani.thatha]

Dear friend,

Which language you use?

I think you have already use hard uart.

In soft uart take two pin ,one for reception and other for transmission.

We used C language. And you are right i already used hard usart for gps and now i am trying to connect soft usart that is took two pins and connected from RXD to RX of male connector and TXD to TX of male connector and GND of male connector to ground. and then this male connector is inserted to the input female port of gsm modem but it is not working.

And i initialized both the usarts USART0 USART2 using their UCSRB UCSRC registers. Is there any necessary modifications please kind enough to suggest.

Is htere any necessary for max232 for this connections or it is sufficeint to connect pins to male and that male to female port of device?

 

[ansarmytheen]

Dear friend,

Yes, you need max 232 connection for both modules.Also,some gsm modem works only in null modem concept.

also please check your softuart alone.

 

[nandhu015]

Another option is to use a multiplexer. The inputs of multiplexer are connected to gps and gsm modems and the output may connected to the micro

Nandhu

 

[sravani.thatha]

Dear friend,

Yes, you need max 232 connection for both modules.Also,some gsm modem works only in null modem concept.

also please check your softuart alone.

thank you very much sir we used one usart from board and another we connected the TXD and RXD pins to max232 with help of bread board and connected to another modem now its working...

---------- Post added at 11:10 ---------- Previous post was at 11:08 ----------

Another option is to use a multiplexer. The inputs of multiplexer are connected to gps and gsm modems and the output may connected to the micro

Nandhu

hai sir,
can you make it a bit clear how the multiplexer is used for both the modems?

 

[nandhu015]

For example you can use
74HC/HCT157 Quad 2-input multiplexer

Refer datasheet for more details

Nandhu