5 Replies Latest reply on Jun 7, 2010 11:53 PM by vishnu.kumar

    gsm modem

    vishnu.kumar

      I am trying to interface gsm modem to psoc.  my problem is that i am sending AT command to system through UART ar baud rate of 4800. i am sending ok from hyperterminal manually. it is getting displayed on the lcd. but when i am doing same thing with gsm modem i am unable to get the result. one more doubt when i am testing gsm modem with system i am typing AT and after that "enter" key  then i am getting response "ok". now how can i send "enter" key function to the gsm from psoc device?

         

       

         

      Thanks & Regards

         

      Vishnu

        • 1. Re: gsm modem
          ganesh.raaja.maharajan

          Make sure that the baud rate of the GSM modem is the same as the PSoC (4800). 

             

          The enter key is nothing but a Carriage Return (CR) and Line Feed character (LF).  For Line feed, the hex value that you need to send is 0x0A.  For Carriage Return you need to send 0x0D.  Check the GSM data sheet for which character you need to send.  If it is only the LF, then you can try the following code.

             

          UART_CPutString("AT\n");

             

          If it is both CR and LF then you could try:

             

          UART_CPutString("AT");

             

          UART_PutCRLF();

          • 2. Re: gsm modem
            vishnu.kumar

            i am using wavecom q2043a gsm modem with 9600 baud (previously i've used 4800 baud  modem)  i've tried same code but unable to get the result. whenever i am connecting to system i  am  getting  the results perfectly. but unable interlink modem and psoc.   

            • 3. Re: gsm modem
              ganesh.raaja.maharajan

              Try the below example project and modify the code accordingly.  Remember, the clock input to the UART should be 8 times the baud rate.  So, in your case for a baud rate of 9600, the clock input should be 76800.  For this set the UART clock to VC3, VC3 source to VC1, VC3 divider to 156.  Also, set VC1 divider to 2.  That should set the UART for 9600  baud rate.

              • 4. Re: gsm modem
                ganesh.raaja.maharajan

                Here is the link to the example project I mentioned in the previous post.

                   

                 

                   

                http://www.cypress.com/?rID=38167

                • 5. Re: gsm modem
                  vishnu.kumar

                  Thanks for the reply. Sir  I got the result, but i have one doubt while i am checking my gsm modem with sytem i am using straight cable i am unable get the result if i am used same cable to the controller. i have interchanged the rx and tx connection of the cable then i've got the result. waht is the reason behind that???

                     

                  Thanks & Regards

                     

                  Vishnu