TinyGSM function (modem.gprsConnect(...)) reset Wemos D1 mini (ESP8266) - Soft WDT reset problem

[Engine1992]

[x] Question or request for help

Modem: SIM800L
Main processor board: WEMOS D1 Mini (ESP8266)
TinyGSM version: 0.11.7
Code:

 #define TINY_GSM_MODEM_SIM800
 #include <TinyGsmClient.h>
 #include <Firebase_ESP_Client.h>
 #include <Ultrasonic.h>
 #include <SoftwareSerial.h>
 
 // Provide the token generation process info.
 #include "addons/TokenHelper.h"
 // Provide the RTDB payload printing info and other helper functions.
 #include "addons/RTDBHelper.h"
 
 // Pin configuratuin for Ultrasonic Sensor
 #define TRIG_PIN D2
 #define ECHO_PIN D1
 float distance = 0;
 Ultrasonic ultrasonic(TRIG_PIN, ECHO_PIN);

 // Var for voltage metter
 int voltageValue;
 float voltage;
 
 // Insert Firebase project API Key
 #define API_KEY ""
 
 // Insert RTDB URL
 #define DATABASE_URL ""
 
 // Define Firebase Data object
 FirebaseData fbdo;
 
 FirebaseAuth auth;
 FirebaseConfig config;
 
 // Pin configuration for SIM800L
 SoftwareSerial SIM800L_Serial(12, 13, false, 128);
 
 // Your SIM card PIN
 #define SIM_PIN ""
 
 // APN settings for your mobile network provider
 #define GPRS_APN "internet"
 #define GPRS_LOGIN ""
 #define GPRS_PASSWORD ""
 
 TinyGsm modem(SIM800L_Serial);
 //TinyGsmClient client(modem);
 
 unsigned long sendDataPrevMillis = 0;
 int count = 0;
 bool signupOK = false;
 
 void setup() {
   Serial.begin(115200);
   delay(10);
   Serial.println("Started Serial");
   SIM800L_Serial.begin(115200);
   delay(3000); // Give SIM800L some time to initialize
   Serial.println("Started SIM800L Serial");
   // Unlock SIM card with PIN
   modem.simUnlock(SIM_PIN);
 }
 
 void loop() {
 
   distance = ultrasonic.read();
   voltageValue = analogRead(A0);
   voltage = voltageValue * (7.2 / 1023.0)*2;
 
   Serial.print("Distance: ");
   Serial.print(distance);
   Serial.println(" cm");
 
   Serial.print("Voltage: ");
   Serial.print(voltage);
   Serial.println(" V");
 
   //Send data through GPRS (SIM800L)
   sendDataThroughGPRS();
 }

 void sendDataThroughGPRS() {
   Serial.println("Connecting to GPRS");
   if (modem.gprsConnect(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD)) {
   Serial.println("Connected to GPRS");
 }
}

Scenario, steps to reproduce

• Arduino IDE - LOLIN(WEMOS) D1 R2 mini board
• Serial speed 115200
• SIM800L connection to Wemos D1 mini (SIM800L RX to D6 and TX to D7)
• SIM800L powered by 2x 18650 3.7v batteries through a voltage regulator (5V)
• Wemos D1 powered by USB
• SIM800L is connected to network (status LED flashes every 3 seconds).
• SIM PIN is disabled

Expected result

I want to make SIM800L works with ESP8266 and finally sent data to Firebase via GPRS.

Actual result

Sensor readings work and are displayed in SERIAL. When I try to call the "modem.gprsConnect(GPRS_APN, GPRS_LOGIN, GPRS_PASSWORD)" function, I get an error "Soft WDT reset":

• 23:02:58.198 -> ������n��r��n|�l�l��b���b�r��l�nB�n�l���r�l�l���Started standard Serial
• 23:03:01.242 -> Started SIM800L Serial
• 23:03:01.242 -> Distance: 25.00 cm
• 23:03:01.242 -> Voltage: 6.97 V
• 23:03:01.242 -> Connecting to GPRS
• 23:03:03.111 ->
• 23:03:03.111 -> --------------- CUT HERE FOR EXCEPTION DECODER ---------------
• 23:03:03.143 ->
• 23:03:03.143 -> Soft WDT reset
• 23:03:03.143 ->
• 23:03:03.143 -> Exception (4):
• 23:03:03.143 -> epc1=0x402156ee epc2=0x00000000 epc3=0x00000000 excvaddr=0x00000000 depc=0x00000000
• 23:03:03.143 ->
• 23:03:03.143 -> >>>stack>>>
• 23:03:03.143 ->
• 23:03:03.143 -> ctx: cont
• 23:03:03.143 -> sp: 3fff0790 end: 3fff09d0 offset: 0160
• 23:03:03.143 -> 3fff08f0: 00000000 00000c17 31eb851e 000dfad1
• 23:03:03.143 -> 3fff0900: 3ffe8c01 00000000 00000c17 0000ea60
• 23:03:03.143 -> 3fff0910: 3fffdad0 00000000 00000c17 00000000
• 23:03:03.175 -> 3fff0920: 3ffe8c09 3ffe8c01 3ffeedf4 40209223
• 23:03:03.175 -> 3fff0930: 00000000 00000000 3ffeee10 3fff0a2c
• 23:03:03.175 -> 3fff0940: 3fff37bc 0000004f 80000000 402134a8
• 23:03:03.175 -> 3fff0950: 402107e0 00000000 3ffeedf4 4020947c
• 23:03:03.175 -> 3fff0960: 00000000 3ffef4f0 3ffef7fc 40213f24
• 23:03:03.175 -> 3fff0970: 3ffe8c77 3ffe8c77 3ffe8bca 40213f24
• 23:03:03.175 -> 3fff0980: 402107e0 3ffe8c75 3ffef7fc 3fff0a2c
• 23:03:03.214 -> 3fff0990: 3fffdad0 00000012 3ffef7fc 3fff0a2c
• 23:03:03.214 -> 3fff09a0: 3fffdad0 00000000 3ffef7fc 4020976a
• 23:03:03.214 -> 3fff09b0: 3fffdad0 00000000 3fff0a00 40212cc8
• 23:03:03.214 -> 3fff09c0: feefeffe feefeffe 3fffdab0 401002dd
• 23:03:03.214 -> <<<stack<<<
• 23:03:03.214 -> --------------- CUT HERE FOR EXCEPTION DECODER ---------------
• 23:03:03.214 ->
• 23:03:03.214 -> ets Jan 8 2013,rst cause:2, boot mode:(3,6)
• 23:03:03.251 ->
• 23:03:03.251 -> load 0x4010f000, len 3424, room 16
• 23:03:03.251 -> tail 0
• 23:03:03.251 -> chksum 0x2e
• 23:03:03.251 -> load 0x3fff20b8, len 40, room 8
• 23:03:03.251 -> tail 0
• 23:03:03.251 -> chksum 0x2b
• 23:03:03.251 -> csum 0x2b
• 23:03:03.251 -> v0006f2d0
• 23:03:03.251 -> ~ld

I tried to use yield(); and delay(0); but not success.