Sparkfun LTE Cat M1/NB-IoT Shield - Unable to communicate serially with the SARA-R410M UART

Wireless & IoT Cellular
1

I just purchased the Sparkfun LTE Cat M1/NB-IoT Shield - SARA-R4. So far I have not been able to communicate serially with this board. Here is what I have tried:

  1. Using the Arduino UNO development board

  • power set to Arduino

  • serial set to Soft

  • power LED is on

  • tried hitting the Power button for 3 seconds (though shouldn’t be necessary as this is also done in the SoftwareSerial library, via the PowerOn() function)

  • tried hitting the reset button for 10 seconds

  • added debug to SoftwareSerial and the begin() code gets stuck in the area where it is trying to determine the correct baud rate

  • voltage on pins 8 and 9 are both about 5v, which I believe is correct as both are pulled high during the initialization

  • also tried powering the LTE Shield using the USB port or the LiPo battery input

  1. Using the Sparkfun Redboard development board
  • same as the UNO (as would be expected since the Redboard is identified as a UNO by the Arduino IDE)
  1. Using the FTDI Header

  • used the Sparkfun FTDI Basic USB-to-Serial converter (this board has been used successfully with the Arduino Pro Mini)

  • tried PuTTY and Tera Team on my PC to communicate (the TX LED lights up on the FTDI Basic when I send) but got no response from the LTE Shield

  • tried Minicom on my RPi with even less response

Not sure what else I can do. Did I miss something obvious? Or is the LTE Shield toast, DOA?

2

Hi djmauro.

Sorry to hear you’re having trouble!

Can you send a clear, high resolution photo of the top and bottom of your board and a photo showing how it’s connected to your Arduino/RedBoard?

Those will help us figure out what might be the issue.

3

Here are the images you requested. Note also that I did no cut any traces nor solder any jumpers. (img tag didn’t seem to work very well)

https://flic.kr/p/2heA8sQ

https://flic.kr/p/2heA8wY

https://flic.kr/p/2heA8ui

https://flic.kr/p/2heA8vq

Regards.

4

Hello djmauro.

Sorry for the delay in getting back to you and thanks for sending those photos. Everything in your photos looks in order and I’m not sure what’s causing your troubles. Can you PM me your order number?