Ai-Thinker A7 GPRS/GPS Error

Using Arduino Networking, Protocols, and Devices
1

Hi everyone,

I used for a long time a GPS/GSM module ( Ai-thinker A7 shield v1.0 ) for my project. Today I had tried another time this module and there were a really unusual behaviour, when I send a particular (AT+GPS=1 or AT+CMGF=1) AT command the shield restars on it own. If I send a simple command, just AT for example or AT+IPR?, everything is fine, the shield answer over the uart.

Below the simple code that I use:

#include <SoftwareSerial.h>

SoftwareSerial cu(7,8);

int var;
char prova;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  cu.begin(115200);

  Serial.println("done!");
 
}

//UART0
void loop(){
  // put your main code here, to run repeatedly:
  if(Serial.available()){
    Serial.println("Send to A7:");
    cu.print(Serial.readString());
    }

  if(cu.available()){
    Serial.println("Receive from A7:");
    Serial.print(cu.readString());
   
    }
  
  delay(100);
  
  }

Anyone know why?

Best Regards,
Vincenzo