AT_Debug.ino

/**************************************************************
 *
 * This script tries to auto-detect the baud rate
 * and allows direct AT commands access
 *
 * TinyGSM Getting Started guide:
 *   http://tiny.cc/tiny-gsm-readme
 *
 **************************************************************/

// Select your modem:
#define TINY_GSM_MODEM_SIM800
//#define TINY_GSM_MODEM_SIM900
//#define TINY_GSM_MODEM_M590

#include <TinyGsmClient.h>

// Set serial for debug console (to the Serial Monitor, speed 115200)
#define SerialMon Serial

// Set serial for AT commands (to the module)
// Use Hardware Serial on Mega, Leonardo, Micro
#define SerialAT Serial1

// or Software Serial on Uno, Nano
//#include <SoftwareSerial.h>
//SoftwareSerial SerialAT(2, 3); // RX, TX

TinyGsm modem(SerialAT);

// Module baud rate
uint32_t rate = 0; // Set to 0 for Auto-Detect

void setup() {
  // Set console baud rate
  SerialMon.begin(115200);
  delay(5000);
}

void loop() {

  if (!rate) {
      static uint32_t rates[] = { 115200, 9600, 57600, 19200, 38400, 74400, 74880, 230400, 460800, 2400, 4800, 14400, 28800 };

      SerialMon.println("Autodetecting baud rate");
      for (unsigned i = 0; i < sizeof(rates)/sizeof(rates[0]); i++) {
        SerialMon.print(String("Trying baud rate ") + rates[i] + "... ");
        SerialAT.begin(rates[i]);
        delay(10);
        if (modem.autoBaud(1000)) {
          rate = rates[i];
          SerialMon.println(F("OK"));
          break;
        } else {
          SerialMon.println(F("fail"));
        }
      }
  }

  if (!rate) {
    SerialMon.println(F("***********************************************************"));
    SerialMon.println(F(" Module does not respond!"));
    SerialMon.println(F("   Check your Serial wiring"));
    SerialMon.println(F("   Check the module is correctly powered and turned on"));
    SerialMon.println(F("***********************************************************"));
    delay(30000L);
    return;
  }

  SerialAT.begin(rate);

  // Access AT commands from Serial Monitor
  SerialMon.println(F("***********************************************************"));
  SerialMon.println(F(" You can now send AT commands"));
  SerialMon.println(F(" Enter \"AT\" (without quotes), and you should see \"OK\""));
  SerialMon.println(F(" If it doesn't work, select \"Both NL & CR\" in Serial Monitor"));
  SerialMon.println(F("***********************************************************"));

  while(true) {
    if (SerialAT.available()) {
      SerialMon.write(SerialAT.read());
    }
    if (SerialMon.available()) {
      SerialAT.write(SerialMon.read());
    }
    delay(0);
  }
}