"SoftwareSerial.h not available" in LilyGo T-Call SIM800

Projects General Guidance
1

Hello, I'm currently programming a code that will send GPS data to the server using MQTT. The device that I use for program is LilyGo T-Call SIM800 (BLYNK V1.4). The program all went okay until I update my Arduino IDE to the latest version, and the error "fatal error: SoftwareSerial.h: No such file or directory" appear. Is there any suggestion for me so I can make my code work again in the latest version of Arduino IDE?

(Note that, it is such a hassle to use another UART because I have to disconnect it before uploading the code to the board)

the code :

// Select your modem:
#define TINY_GSM_MODEM_SIM800 // Modem is SIM800L

// Set serial for debug console (to the Serial Monitor, default speed 115200)
#define SerialMon Serial
// Set serial for AT commands
#define SerialAT Serial1

// Define the serial console for debug prints, if needed
#define TINY_GSM_DEBUG SerialMon

// set GSM PIN, if any
#define GSM_PIN ""

// Your GPRS credentials, if any
const char apn[] = "my3g"; // APN
const char gprsUser[] = "";
const char gprsPass[] = "";

// SIM card PIN (leave empty, if not defined)
const char simPIN[]   = ""; 

// MQTT details
const char* broker = "test.mosquitto.org"; // Public IP address or domain name
const char* mqttUsername = "";  // MQTT username
const char* mqttPassword = "";  // MQTT password


const char* topicGPS = "things/product/2g/94E686DFA95C/osd";


// Define the serial console for debug prints, if needed
//#define DUMP_AT_COMMANDS

#include <Wire.h>
#include <TinyGsmClient.h>
#include <TinyGPS++.h>
#include <SoftwareSerial.h>

int RXPin = 35;
int TXPin = 34;

int GPSBaud = 9600;

TinyGPSPlus gps;

SoftwareSerial gpsSerial(RXPin, TXPin);

#ifdef DUMP_AT_COMMANDS
  #include <StreamDebugger.h>
  StreamDebugger debugger(SerialAT, SerialMon);
  TinyGsm modem(debugger);
#else
  TinyGsm modem(SerialAT);
#endif

#include <PubSubClient.h>

TinyGsmClient client(modem);
PubSubClient mqtt(client);

// TTGO T-Call pins
#define MODEM_RST            5
#define MODEM_PWKEY          4
#define MODEM_POWER_ON       23
#define MODEM_TX             27
#define MODEM_RX             26
#define I2C_SDA              21
#define I2C_SCL              22


uint32_t lastReconnectAttempt = 0;

// I2C for SIM800 (to keep it running when powered from battery)
// TwoWire I2CPower = TwoWire(0);

// #define IP5306_ADDR          0x75
// #define IP5306_REG_SYS_CTL0  0x00

long lastMsg = 0;

// bool setPowerBoostKeepOn(int en){
//   I2CPower.beginTransmission(IP5306_ADDR);
//   I2CPower.write(IP5306_REG_SYS_CTL0);
//   if (en) {
//     I2CPower.write(0x37); // Set bit1: 1 enable 0 disable boost keep on
//   } else {
//     I2CPower.write(0x35); // 0x37 is default reg value
//   }
//   return I2CPower.endTransmission() == 0;
// }

void mqttCallback(char* topic, byte* message, unsigned int len) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageTemp;
  
  for (int i = 0; i < len; i++) {
    Serial.print((char)message[i]);
    messageTemp += (char)message[i];
  }
  Serial.println();

  // Feel free to add more if statements to control more GPIOs with MQTT

  // If a message is received on the topic esp/output1, you check if the message is either "true" or "false". 
  // Changes the output state according to the message
}

boolean mqttConnect() {
  SerialMon.print("Connecting to ");
  SerialMon.print(broker);

  // Connect to MQTT Broker without username and password
  boolean status = mqtt.connect(broker);

  // Or, if you want to authenticate MQTT:
  //boolean status = mqtt.connect("GsmClientN", mqttUsername, mqttPassword);

  if (status == false) {
    SerialMon.println(" fail");
    ESP.restart();
    return false;
  }
  SerialMon.println(" success");

  return mqtt.connected();
}


void setup() {
  // Set console baud rate
  SerialMon.begin(9600);
  gpsSerial.begin(GPSBaud);
  delay(10);
  
  // // Start I2C communication
  // I2CPower.begin(I2C_SDA, I2C_SCL, 400000);
  
  // // Keep power when running from battery
  // bool isOk = setPowerBoostKeepOn(1);
  // SerialMon.println(String("IP5306 KeepOn ") + (isOk ? "OK" : "FAIL"));

  // Set modem reset, enable, power pins
  pinMode(MODEM_PWKEY, OUTPUT);
  pinMode(MODEM_RST, OUTPUT);
  pinMode(MODEM_POWER_ON, OUTPUT);
  digitalWrite(MODEM_PWKEY, LOW);
  digitalWrite(MODEM_RST, HIGH);
  digitalWrite(MODEM_POWER_ON, HIGH);

  
  SerialMon.println("Wait...");

  // Set GSM module baud rate and UART pins
  SerialAT.begin(115200, SERIAL_8N1, MODEM_RX, MODEM_TX);
  delay(6000);

  // Restart takes quite some time
  // To skip it, call init() instead of restart()
  SerialMon.println("Initializing modem...");
  modem.restart();
  // modem.init();

  String modemInfo = modem.getModemInfo();
  SerialMon.print("Modem Info: ");
  SerialMon.println(modemInfo);

  // Unlock your SIM card with a PIN if needed
  if ( GSM_PIN && modem.getSimStatus() != 3 ) {
    modem.simUnlock(GSM_PIN);
  }

  SerialMon.print("Connecting to APN: ");
  SerialMon.print(apn);
  if (!modem.gprsConnect(apn, gprsUser, gprsPass)) {
    SerialMon.println(" fail");
    ESP.restart();
  }
  else {
    SerialMon.println(" OK");
  }
  
  if (modem.isGprsConnected()) {
    SerialMon.println("GPRS connected");
  }

  // MQTT Broker setup
  mqtt.setServer(broker, 1883);
  mqtt.setCallback(mqttCallback);
}

void loop() {
  if (!mqtt.connected()) {
    SerialMon.println("=== MQTT NOT CONNECTED ===");
    // Reconnect every 10 seconds
    uint32_t t = millis();
    if (t - lastReconnectAttempt > 10000L) {
      lastReconnectAttempt = t;
      if (mqttConnect()) {
        lastReconnectAttempt = 0;
      }
    }
    delay(100);
    return;
  }

  long now = millis();
  while (gpsSerial.available() > 0)
    if (gps.encode(gpsSerial.read()))
       if (gps.location.isValid())
  {
        String json = "{";
    json += "\"satellite\": " + String(gps.satellites.value());
    json += ", \"latitude\": " + String(gps.location.lat(), 6);
    json += ", \"longitude\": " + String(gps.location.lng(), 6);
    json += ", \"altitude\": " + String(gps.altitude.meters());
    json += "}";

    // Publish JSON string to MQTT broker
    char payload[json.length() + 1];
    json.toCharArray(payload, sizeof(payload));
    mqtt.publish(topicGPS, payload);
    Serial.println(payload);
  }
  else
  {
    Serial.println("Location: Not Available");
  }

  // If 5000 milliseconds pass and there are no characters coming in
  // over the software serial port, show a "No GPS detected" error
  if (millis() > 5000 && gps.charsProcessed() < 10)
  {
    Serial.println("No GPS detected");
    while(true);
  }
  mqtt.loop();
}

If any other questions, feel free to ask. Thanks!

2

As you can set a hardware serial on any IO pin on the ESP32 you don't need a software emulation on that system. You have 3 hardware UARTs on an ESP32.

I don't see the reason for this.

3

I do know ESP32 have 3 hardware UARTs. The problem is, LilyGo T-Call SIM800 are build using ESP Wrover E as its brain, which is have two UART, UART0 and UART1. Unfortunately, UART0 are used for serial communication and UART1 are used for SIM800 communication. I have to assign another GPIO to be external UART for GPS module (Neo 6M GPS). I have try HardwareSerial.h and assign it to another GPIO, but it seems error shows pin interruption error.

Update : I have success in implementing the SoftwareSerial.h using the same code, and not disturb any line in the code. New problem came out : connecting to MQTT public server (test.mosquitto.org) fail but that is another topic to discuss

4

Where did you find that information that the WroverE does contain a special version of the ESP32 with less UARTs? The datasheet doesn't mention such an exception. So I think you can use the third serial interface (Serial2) and just define the pins you want to use. Have you tried that?

5

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