Hey guys. I have a problem with interfacing my bluetooth module (aubtm-20) with Atmega 640. The BT module works perfectly and responds to the commands sent when connected directly to a PC. I have also debugged the code and it works perfectly. But when I connect the BT module (Rx and Tx pins are connected to MAX232 and then to DB9 connector) to the microcontroller using DB9 connector + MAX232, I get incomplete response.
For example, instead of getting getting the response as “OK”, I get a response like “O”. The response I get seems to be a part of the actual response but I get a different response everytime.
Rx of BT module is connected to Tx of microcontroller and Tx of BT module is connected to Rx of microcontroller.
I also have shorted grounds of both the boards and have ensured that the baud rates are proper.
Please let me know what the problem could be.