Sketch wont work when shield is mounted on arduino

Hi Guys,
I tried uploading a sketch on my arduino board, when NB IOT shield is mounted on it. unfortunately it wont work. Funny part is, i removed the shield from my board and tries uploading the sketch on board, the sketch gets uploaded and start working but strange thing is once i put the shield back on board, it stop working… any suggestions please


What board are you using?
If it’s an Arduino Uno please use the search function of the forum.


Hi Jan,

My board is Intel Genuino 101, I can not upload the sketch when shield is mounted, even i did upload by removing the shield but when i keep the shield back on board, the program never runs.need ur expertise on this too.

Thank you


Did you update the sketch to use SerialUSB or Serial (both work) for the usb and Serail1 for the communication to the shield?


Yes… I have done the same and did not get any success as of now.

If the same Serial / UART is connected both to the USB and to pins 0 / 1 on the shield, they you must have the shield disconnected while programming the board.

Additionally, if you want to try the pass through sketch, you will have to have the shield disconnected and wire it up using a software serial.

Guys, give me a specific answer.
I am reading it over n over on UART issue, ok fine.
I am using as below :slight_smile:

SoftwareSerial softSerial(10, 11); // RX, TX
// You can connect an uartsbee or other board (e.g. 2nd Uno) to connect the softserial.
#define DEBUG_STREAM softSerial
#define MODEM_STREAM Serial

From my intel board, i am connecting following pins to NB IOT shield, PIN-0—>0 (Rx) 1---->1 (Tx) 7---->7(Enable Shield), 13------>13

I am printing the serial output using Debug_Stream but no success why is it so


Pin 7 , Pin 13, 3.3v Pin & GND pin are connected with NB IOT shield, SOftware serial 10, 11 are connected to ttl2 usb still there is no success, even if i comment out the connection part, till i wont see SODAQ shield working… what might be the issue ?

Can you connect the ioref?

Rx Arduino - Tx NbIoT shield
Tx Arduino - Rx Nbiot shield
Same for the external usbttl2 rx to tx and tx to rx.
I dont have a Arduino 101 to replicate the issue, I have to use google too :slight_smile:

Nb-iot shield is tested on a Leonardo, Explorer and M0.

Hope this helps you finding the issue.


1 Like

Hi Jan,
Done the things you suggested, still no issue…
COuld you please check if we are missing some check on library side, which we need to implement on PIN side.