I want to connect GSM module and RFID detector module with ATMEGA16.
Here, the purpose of the RFID detector and GSM module is
When an unauthorized RFID card will be scanned, GSM module will make a call to a certain phone number.
But the problem is that,
When I connect both the transmitter with the RX of the ATMEGA16(as shown in the figure), GSM module does not initiates. And even the RFID module also not detects card value.
But individually GSM INITIATES piety well.
What should be the probable problem? Is this Circuit connection issue? Or Coad Issue?
C Code and USART header file is given below.