Cannot pass AT commands to shield

Hardware Portenta Portenta CAT.M1/NB IoT GNSS Shield
1

I am having no success trying to send AT commands to the modem and reading them in the serial monitor. I've borrowed from a number of different sketches I found online but none have worked. This is my latest attempt:

#include "Serial.h"

UART myUART0(PA_0,  PI_9,  NC, NC); //TX, RX, RTS, CTC  NOTE: NC means not connected
UART myUART1(PA_9,  PA_10, NC, NC);
UART myUART2(PG_14, PG_9,  NC, NC);
UART myUART3(PJ_8,  PJ_9,  NC, NC);

void setup(){
  myUART0.begin(115200);
  myUART1.begin(115200);
};



void loop(){
  if(myUART0.available()>0){
    byte b=myUART0.read();
    myUART1.write(b);
  }
  if(myUART1.available()>0){
    byte b=myUART1.read();
    myUART0.write(b);
  }
};

I've tried different combinations of myUART"x" and myUART"y" but no matter what I try, I get nothing from the serial monitor. I cannot even get an echo to come back when I enter a command - so If I try "AT" + ENTER with new line and carriage return both selected, nothing shows up in the serial monitor, not even "AT".

Can anyone help a newb whose in way over his head?

2

You have posted the same question in Not able to send AT commands using Portenta H7 CatM1/NB IoT GNSS shield which was closed.

Cross-posting is against the Arduino forum rules. The reason is that duplicate posts can waste the time of the people trying to help. Someone might spend a lot of time investigating and writing a detailed answer on one topic, without knowing that someone else already did the same in the other topic.

Please create one topic only for your question and choose the forum category carefully. If you have multiple questions about the same project then please ask your questions in the one topic as the answers to one question provide useful context for the others, and also you won’t have to keep explaining your project repeatedly.

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Could you take a few moments to Learn How To Use The Forum. It will help you get the best out of the forum in the future.

Thank you.

the discussion can happen here in this thread