I am working on as SMS-based system. The system includes SIM900 GSM/GPRS module from which Arduino is supposed to read SMS.
When I used AT+CMGR command from a Terminal program to manually read SMS from the module, I was able to read the complete SMS. Please see attached image named: "Using Terminal". However, when I try to read the SMS from Arduino using the sketch I attached , I got incomplete message. Please see attached image named: "Using Arduino".
I have tried all I could to fix this issue to no avail. Kindly help! I attach the Arduino sketch for your assistance.
Waiting three seconds until processing the response may cause the serial buffer to get full and the rest of the message may be lost.
I suggest you wait up to three seconds but process the response character by character as soon as data is available.
Is this helpfull:
boolean ReadGSMRXDataResponse(const String &p_resp, const int &p_max_response_seconds) {
//Many commands have a standard 5 sec max response time, others twenty or sixty seconds
//Sending an SMS has a max 60 second response time (it allows for poor network connectivity/retries)
//Prior to sending any AT command we cleared the Serial1 Rx buffer.
//So we do not expect an extraneous response related to a previous long running command.
//Iterate for the response delay until we have received the first character of the response
unsigned long l_timer = millis();
while (!CheckSecondsDelay(l_timer, p_max_response_seconds * 1000)) {
if (Serial1.available()) {
break;
}
}
//Once any response character is received we assume we have the whole response
//ReadGSMRxData includes a 250ms delay between characters to
//allow for a response that is still coming.
ReadGSMRXData();
String l_resp = p_resp;
l_resp.trim();
if (G_GSMRXData == "") {
if (G_SerialOn)
Serial.println(F("No Data Received"));
//
CheckFreeSRAM();
return false;
}
else if (l_resp == "") { //No particular response is expected
CheckFreeSRAM();
return true; //The response can be ignored
}
else if (G_GSMRXData.indexOf(l_resp) != -1) {
//We may want to trim the expected response (OK) off G_GSMRXData
CheckFreeSRAM();
return true;
}
//We may have expected OK but got an ERROR.
//Or we may have suffered a comms error and recd garbage.
if (G_SerialOn) {
Serial.print(F("Response Not Found - "));
Serial.println(G_GSMRXData);
}
CheckFreeSRAM();
return false;
} //ReadGSMRXDataResponse
//----------------------------------------------------------------------------------------------
void ReadGSMRXData() {
//Available data is known to be in the RX buffer
//Read it and return via G_GSMRXData
//Application wide this is the only place we do Serial1.read()
G_GSMRXData = "";
unsigned long l_timer = millis();
while (!CheckSecondsDelay(l_timer, 250)) {
while (Serial1.available()) {
char l_char; //Always read a char, then append char to G_GSMRXData String
l_char = Serial1.read();
G_GSMRXData += l_char;
l_timer = millis(); //reset qtr sec timer
}
}
G_GSMRXData.trim();
//No need to force uppercase
CheckFreeSRAM();
} //ReadGSMRXData
//----------------------------------------------------------------------------------------------
