Interfacing Telit GT863-PY gsm module and microcontroller

[pashok84]

Hi All,

I am trying to interface MSP430 microcontroller and Telit GT863-PY module. I am facing a problem. microcontroller is not able to communictate with gsm module.

When i test the microcontroller with PC serial port it is working and gsm module is also working individual with PC.
when i connect microcontroller with GSM module, it is not working. I thought it might be because of flow control, as in microcontroller side only 3 pins are connected.
After disabling Flow control also problem exists.

Can anyone give sugesstion to debug further, or anyone faced similar issue earlier.

Setup

Microcontroller <=> RS232 cable <=> GSM modem.

Thanks and Regards,
Ashok Kumar P

 

[aameer]

Does your GSM module has built in Max232?? if so Make the RS232 cable connection as like this. reverse that is at 1 end of DB9 connect 2 -Rx,3-Tx,5-gnd and on the other end of cable make 2-tx,3-Rx,5-gnd... then Try.. hope you will get the output.

 

[pashok84]

Hi Aameer,

Thanks you very much.
You are correct. i need cross cable to make it work.
I have been debugging why data is not coming out of micro controller, it is because both being Tx on the same pin Modem is pulling it low so my data is not received.
I need 2 Tx - 3 Rx 3 Rx - 2 Tx 5 - 5 GND

Thanks and Regards,
Ashok Kumar P