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.
Well, you need to understand what is actually happening in your systems.
If displaying stuff on an LCD works for you - then do it.
Other alternatives could be send stuff out of a serial port.
Or blink some LEDs
Or use a modern chip with on-board debug.
Maybe monitor the exchanges between the MCU and modem; eg, see "Debugging Serial Comms" here: www.avrfreaks.net/.../2416751
Or a combination of the above.
Debugging is a key skill in any form of development - hardware, software, whatever: www.avrfreaks.net/.../2418156
Thank you so much Andrew Neil.. I will try all the possible things you maintained... Hope it will definitely solve my problem . if i am having problem again i will again contact you.. thanks again for your guidance..
hello Andrew Neil... i have tried almost all the suggestions you maintained in previous reply.. i tried to display it on lcd bt it shows nothing.. i tried to blink LEDs it didn't work.. and instead of tera term i do connection with putty.. i.e microcontroller to gsm and its connection to usb to ttl in putty.. nothing worked.. what i am doing wrong??