sms recieving problem using sim900d

[M.Imran Ali]

hi
i am using pic18f452 interfaced with sim900d , It is working f9 only problem is , i am using RDA interrupt and when there is an sms rcievied and modem puts +CMTI: "SM",1 it does not go to interrupt?
Any one have experience like this problem plz share

 

[AbdulMoeez]

sometimes pic microcontroller don't received sms on rda from sim900d module because of different voltage levels used for both. operate pic on 3.3 v or add logical converter on rx of pic to match logic level. add 2 diodes in vcc series of microcontroller it also work. i faced this problem many times so now i got its solution......

 

[M.Imran Ali]

actually i am using a gsm evalution board that has rs232 in it so rs232 on both sides? So still there is any level logic problem?

 

[AbdulMoeez]

if you using that board , there will no logic level problem. recheck your code problem is in code i think...............

 

[M.Imran Ali]

when i send 'AT' and it goes to interrupt when modem sends OK and so on but when message comes it does not goes to interrupt that is my problem?

 

[jayanth.devarayanadurga]

Post code.