[AVR] Serial Port interfacing problem

[Rajashri.Shevale]

Hii , I am interfacing sim900a to the Atmega32 microcontroller and also checking its status on PC via DB9 connector. It is working well when I entered AT commands manually but when I am doing same thing by programming it shows garbage value on PC..I don't know why this is happening???

 

[pic.programmer]

Post your code. If possible zip and post your project files. Also port your Circuit. Are the baudrate generated by AVR correct ? What Compiler are you using to write the code ? What is the clock frequency ?

 

[Rajashri.Shevale]

Post your code. If possible zip and post your project files. Also port your Circuit. Are the baudrate generated by AVR correct ? What Compiler are you using to write the code ? What is the clock frequency ?

I am using AVR studio for compilation with 8Mhz frequency, and giving baud rate 9600

 

[pic.programmer]

Disconnect SIM900 for AVR. Connect AVR's UART to PC using MAX232 and DB9 Connector or use TTL2USB adapter between AVR's UART and PC and see if you receive the AT commands send by AVR. If you see garbage on PC then it is surely a baudrate problem.

 

[hamidooon]

First if you have Proteus simulator then make your circuit in that
Use terminal in Proteus.
Load hex file and play simulation ....
See at commands in virtual terminal window..
If necessary try to post your code here