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GSM mdule
Posted: Wed Apr 28, 2010 1:56 pm
by aerofrick
So, under post is a program, where I send command AT+CMGI=? to GSM modul (Falcom A2D). GSM modul then must give me answer OK, but I don't give anything. Maybe do you know where is a problem? (Maybe in delays or in recieve macro?)
The answer must be shown on LCD in second line.
I use PIC16F876A and also MAX232 for TTL to RS232 voltage level converter.
Thanks for the help
Re: GSM mdule
Posted: Wed Apr 28, 2010 2:25 pm
by Benj
Hello,
First of all I would try removing the 500ms delay between sending out the data and receiving the data.
If you have Flowcontrol available on the GSM module then I suggest you use it as this could also help to solve the issues.
If neither of the above help then you may want to check if the GSM echoes everything you send to it as your sending it. If it does then while you are sending the string the GSM is talking back and will cause the RS232 receive buffer to overflow before we get to the part where we are reading in the data. If this is the case then you can enable a fairly fast timer interrupt to perform a read byte function every now and then to ensure the buffer does not overflow.