Hello.. I am doing one project in which msg from GSM is read and it is Displayed to LCD. but microcontroller 89v51 and GSM900A does not communicate every time.. sometimes it successfully happen that AT command from microcontroller is send to GSM and message from any no. to GSM is Displayed to LCD.. bt it's not happening everytime.. i am not getting the solution, Please help.. I have connect 12V,2A supply to GSM.. Microcontroller Rx pin connected to Tx of GSM.. Microcontroller Tx pin Connected to Rx of GSM.. and Ground to Ground.. Please help me. what may be the problem? and how should i fix that.
Sounds like you need to pick a system that's easier to debug or instrument.
Perhaps you should start by coding your application/automation so it runs on a PC via the COM port, so your app talks in place of Putty/Terminal.
This way C code running on the PC can using printf, files, time, etc to debug and better understand the interaction. Unless you can program proficiently on a PC you're going to have an uphill battle programming on an embedded target with difficult/limited internal visibility.
so u r saying instead of using proteus and the real hardware . i should interact the GSM with the PC using Serial communication. And not to use Putty!! & to understand completely the working of GSM connecting it with PC. Like how it responds and all using C. so please tell me any best software so that i can make communication of GSM nd PC and send commands by C CODE..
Is the Proteus approach working well for your programming/debugging style?
You'd use a Microsoft or GNU C compiler, the serial port access could be abstracted via a couple of subroutines so ostensibly the same core code could be run on the PC or 8051.
Get the automation and interaction figured out without the circus of a black box you have minimal internal visibility into.
Note that the uVision simulator can direct its simulated UART output to a COM port, and can receive input from a COM port into the simulation:
www.keil.com/.../uv4cl_sm_uartcommunication.htm
See: www.avrfreaks.net/.../2306116
And: www.avrfreaks.net/.../2417261