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Topic: Confirming AT Command Response and Possibly Resending (Read 91 times) previous topic - next topic

dwalker2020

Hello All,

I'm trying to implement cellular connectivity using an Adafruit FONA. The Adafruit library uses software serial, which doesn't play nice with the RTOS that I'm trying to use, so I'm writing some code that uses UART 2 on the mega2560.

I made a small test sketch to send me a text message every 30 seconds, which works great. Unfortunately, I don't confirm the FONA's response before sending more commands; I'm using hardcoded delays between commands. For instance, I would like to resend "AT" until I get the "OK" response.

It looks like Adafruits library does not try to resend; the "sendCheckReply" function returns a boolean for if the response matches the desired response, but the boolean is never checked.

Any ideas for how to do implement a resend? Thanks for your time.
Code: [Select]

/*
 This code is written to use UART #2 on an Arduino Mega2560 to send an SMS message to a fixed number every 30 seconds.
 It is pretty dumb, but it's a proof of concept of the AT commands being used correctly without a library
 that usually use SoftwareSerial.
 */
 
#define FONA_RST 4 //reset pin on the FONA is connected to Arduino pin 4, different than the stock FONA shield

//-------------------------------------------------------------------------------------

void setup() {
  //start up the serial for debugging
  while (!Serial);
  Serial.begin(115200);
  Serial.println(F("FONA SMS test"));

  //reset the FONA for good measure
  pinMode(FONA_RST, OUTPUT);
  digitalWrite(FONA_RST, HIGH);
  delay(10);
  digitalWrite(FONA_RST, LOW);
  delay(100);
  digitalWrite(FONA_RST, HIGH);
  Serial.println(F("FONA is restarting now, give it a sec"));
  delay(10000); // give 10 generous seconds to reboot

  //start up FONA connection and try to get the FONAs attention
  Serial2.begin(9600);
  Serial.println(F("Sending out AT")); //debug
  Serial2.println("AT"); //  response "OK";
  delay(1000);
 
}

//-------------------------------------------------------------------------------------------

void loop() {
  //Set FONA in Text Mode
  Serial.println(F("Setting system to text mode"));
  Serial2.println("AT+CMGF=1"); // AT command for set system into text mode, expect response OK
  delay(1000);

//forming the SMS address and message body
  Serial.println(F("sending sms"));
  char sendto[21];
  char smsMsg[128];
 
  String number= "+XXXXXXXXXXX"; //replace with an actual phone number
  String message = "It worked!";
 
  number.toCharArray(sendto,21);
  message.toCharArray(smsMsg,128);
 
//debug output of the address and message
  Serial.print("Message Sending to: ");
  Serial.println(sendto);
  Serial.print("Body of message: ");
  Serial.println(smsMsg);

//form the SMS address command using the given phone number and the AT command
  char sendcmd[30] = "AT+CMGS=\"";
  strncpy(sendcmd+9, sendto, 30-9-2);  // 9 bytes beginning, 2 bytes for close quote + null
  sendcmd[strlen(sendcmd)] = '\"';

//send the SMS address command
  Serial2.println(sendcmd);
  delay(1000);

//send the SMS message body
  Serial2.println(smsMsg);
  Serial2.write(0x1A); //CTRL+Z, which is ASCII character 26, to terminate message body 
  Serial.println(F("sent SMS"));

  delay(30000);
}


PaulS

Quote
It looks like Adafruits library does not try to resend; the "sendCheckReply" function returns a boolean for if the response matches the desired response, but the boolean is never checked.
It doesn't look like you are using that library, or Adafruit's forum to report the problem, so I guess it doesn't matter.

Quote
Any ideas for how to do implement a resend?
A pair of while loops. The outer one sends the message over and over, until the correct response is received. The inner one checks, for a period of time or until the complete reply is received, and breaks out, after setting a flag that the outer one checks, when the correct response is received.

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