nRF9160 DK stopped responding to AT commands

[stevenminnick]

I have 2 nRF9160 DK's.  I've been using 1 for most of my testing and the second one was still in the box. 

I loaded the secure boot and the AT_CLIENT demo project.  Opened up the nRF Link Monitor tool.  Hit the reset button and Zephyr stuff flies on the screen.  Ends up with:

Secure Boot: prepare to jump to Non-Secure image

***** Booting Zephyr OS v1.13.99-ncs2 *****

The AT host sample started.  err=0

(I added the err=%d) in the printf statement to prove that I was doing stuff. 

The problem is when I send it an AT command, I get: Error: 'AT ' timed out

I reloaded the modem firmware with: nrf9160_mdm_dfu --update 

That worked.  But still did not respond to AT commands, just time out.

Took my other dev kit out of the box.  Moved my sim card to DevKit #2.  Loaded the same code on it.  With this: nrfjprog.exe --program zephyr.hex --sectorerase -r -f nrf91 --verify

Reboot DevKit #2, and get the same Zephyr messages and everything works.  AT commands work.  Connects to the network. 

Hook back up to DevKit #1, AT commands time out. 

Now I did solder on a 1 ohm resistor on R60 to measure current.  And if I program the asset tracker software to it, it connects and works perfectly.  But why does the AT_CLIENT time out now? 

Anyone have any thoughts?  Thanks!

Steve

[stevenminnick]

Basically I have 2 dev kits.  The asset tracker application works on both of them.  But the at_client software only works on 1 of them. 

The 1 where the at_client doesn't work I was trying to use the IDE to debug, trying to step through.  But I ended up just using the programmer and erasing the whole memory and cloning the second dev kit and the at_client still doesn't work. AT commands just time out.  But it works perfectly on the second dev kit. 

[Bjørn Kvaale]

Have you tried to reset the board multiple times by pressing the RESET button. Erase the flash via nrfjprog --eraseall -f nrf91, then program the secure_boot example via Segger Embedded Studio & finally program the at_client example. Then, open up the Link Monitor application from nRF Connect for Desktop & connect to the board. Then, press the reset button. If the AT commands time out, try to press the reset button again. For some reason, this sometimes works!

Also, once you see the text "The AT host sample started", wait a few seconds & then try pressing the AT+CFUN? button. That should then make the at client example work.

[stevenminnick]

Multiple resets didn't seem to help. 

But blowing out the memory with nrfprog.exe and the programing the secure boot and at client with nrfprog.exe DID work.  It seems to be working fine. 

Why would that work and using the nRFConnect Programming GUI, erasing all and then programming both of those with that tool (multiple times) not work?  On the nRFConnect Link Monitor, both show the same behavior in the terminal window.  Except programming the same HEX files with the GUI produced AT Timed Out and then programming with the command line tool seemed to fix it.

That's weird.  Glad it's working but I'm a little worried about functionality in the future, if something weird happens as I develop code what is my bug and what is whatever happened here. 

[Pratik]

I have similar problem. But in SDK v0.4.0 secure_boot is not available ? Ads it is gone there must be some replacement/other config for replacing it in new version. Can you please clarify it ? Do i need to use old SDK for AT client ?

With new SDK there are 2 Board options for nrf9160 which are nrf9160_pca10090 & nrf9160_pca10090ns.

if i select nrf9160_pca10090 then i get build error for at_client example & with nrf9160_pca10090ns i can build and run, but there is no response for at commands

can you please help me out..?

[stevenminnick]

I didn't notice that till you said it, but yes.  SecureBoot is gone.  I'm not sure why.  You could roll back to 0.3.0 and get it.  Or I had it and included it here.  if you load that on your board that had the at client

nrfjprog.exe --program Secure_Boot.hex --sectorerase -r -f nrf91 --verify

Reset and see if it runs.  Or even make sure the compiled hex file AT_Client.hex (that you made) is loaded with the same tool.  See if that helps. 

I would also like to know what happened to the secureboot project and what we should use now?

0028.Secure_Boot.hex