PSM (Power Save Mode): how to communicate with SARA?

Official Hardware MKR Family MKR NB 1500
1

Working with MKR NB1500 how I'm supposed to communicate with SARA when it is in PSM?

With sketch below I can see that SARA is in PSM and therefore it stops responding to commands. I was thinking that after one hour I can just type some AT-command to serial to see if SARA is awake, but obviously it doesn't work like that.

So if I have defined for example "Requested_Periodic_TAU" = 1 hour and "Requested_Active_Time" = 10 seconds, do I have to track in processor firmware when 1 hour has gone and then I have 10 seconds time to send data to server? Or how does it work?

#include <MKRNB.h>

const char PINNUMBER[] = "";

NBClient client;
GPRS gprs;
NB nbAccess(true);



void setup() { 
  pinMode(SARA_RESETN, OUTPUT);
  digitalWrite(SARA_RESETN, LOW);

  pinMode(SARA_PWR_ON, OUTPUT);
  digitalWrite(SARA_PWR_ON, HIGH);                                  // Send Poweron pulse
  delay(200);
  digitalWrite(SARA_PWR_ON, LOW);
  
  SerialSARA.begin(115200);
  
  Serial.begin(115200);
  while (!Serial);

  boolean connected = false;

  while (!connected) {                                        // After starting the modem with NB.begin()
    if ((nbAccess.begin(PINNUMBER) == NB_READY) &&            // attach to the GPRS network with the APN, login and password
        (gprs.attachGPRS() == GPRS_READY)) {
      connected = true;
    } else {
      Serial.println("Not connected");
      delay(1000);
    }
  }

    
  Serial.println("→ Enabling PSM for 60min...");
  Serial.println();
  
  SerialSARA.println("AT+CPSMS=1,,,\"00100001\",\"00000111\"");
  delay(2000);
  SerialSARA.println("AT+CPSMS?");  
}



void loop() {
  if (Serial.available()) {
    SerialSARA.write(Serial.read());
  }

  if (SerialSARA.available()) {
    Serial.write(SerialSARA.read());
  }
}

Serial response:

AT

OK
AT+CMEE=0

OK
AT+CFUN=0

OK
AT+CPIN?

+CPIN: READY

OK
AT+CMGF=1

OK
AT+UDCONF=1,1

OK
AT+CTZU=1

OK
AT+CGDCONT=1,"IP",""

OK
AT+UAUTHREQ=1,0

OK
AT+CFUN=1

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,0

OK
AT+CEREG?

+CEREG: 0,2

OK
AT+CEREG?

+CEREG: 0,2

OK
AT+CEREG?

+CEREG: 0,5

OK
AT+CGATT=1

OK
AT+CGACT?

+CGACT: 1,1

OK
→ Enabling PSM for 60min...

AT+CPSMS=1,,,"00100001","00000111"

OK
AT+CPSMS?

+CPSMS:1,,,"00000110","00000111"

OK

Thanks,
tipo

2

My guess would be to activate a WAKE interrupt input, then use AT commands normally. Check the SARA user manual.

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