AT_CLIENT app not working

[David Zapata]

Hello,

I have a Thingy91 pca20035 board (not the DK). So far, I have had success building my own modifications of the asset_tracker application by building it using SES and loading the HEX file into the device by using the nRF connect programmer. 

My issue is that I am not able to make the AT_CLIENT work. I tried programming the device with the default HEX file (both the image_dfu and the image_full version) found in https://www.nordicsemi.com/Software-and-Tools/Prototyping-platforms/Nordic-Thingy-91/Download#infotabs (the asset_tracker application found there works just fine). I have tried both COM ports in the nRF connect LTE link monitor. I have also the "auto device/port filter" option unchecked. I have tried turning on and off the device as well as reloading the LTE Link Monitor several times. All I see is this:

Additionally, the UART, Modem, UICC and LTE indicators are red color, while the PDN indicator is grey in the LTE Link Monitor.

It would be nice if you guys have any suggestion?

[Heidi]

Hi!

Since you mention trying both image_full and image_dfu_hex, how are you actually flashing the application to your device? Are you flashing over USB using MCUBoot, or using a debugger (like the nRF960 DK)? 

Best regards,

Heidi

[David Zapata]

Hi Heidi,

As I wrote in my question, I am loading the HEX image into the device using the nRF connect "programmer". I guess "programmer" uses MCUBoot deep inside, but I really don't know. 

 

After writing my question, I kept plugging and unplugging the device, resetting the LTE Link Monitor and turning on and off the device (since that was one suggestion for one similar question) and it worked just once! HOWEVER, I was not able to make it work again. So I suspect something funky is happening. I tested with another USB cable, but I saw no difference. 

[Heidi]

Hi, so you're not using a debugger but just trying the load the hex file onto the PCA20035 board directly with USB? Did you follow these steps?

If you want to use MCUboot, please see this tutorial on how to do that.

[David Zapata]

Yes, I followed those steps for loading the HEX image into the Thingy91 PCA20035. It has worked so far several times for me.

I am sure the AT_CLIENT image is correctly loaded into the device since after trying to connect to LTE Link Monitor a few more times (using the same HEX image), it connected once (but only once). I was not able to make a successful connection again. Is that a known issue? Could it be that the device is waiting for something before being able to respond to AT commands?

[Heidi]

No, this isn't a known issue. There could be something wrong with your device.

Could you send over the log file from LTE Link Monitor? Or is it completely empty? 

What AT Commands are you trying to send to the modem?

[David Zapata]

This is the log file:

2020-03-18T09:00:01.729Z INFO Application data folder: C:\Users\zdiva\AppData\Roaming\nrfconnect\pc-nrfconnect-linkmonitor
2020-03-18T09:00:01.791Z DEBUG App pc-nrfconnect-linkmonitor v1.1.1 official
2020-03-18T09:00:01.792Z DEBUG App path: C:\Users\zdiva\.nrfconnect-apps\node_modules\pc-nrfconnect-linkmonitor
2020-03-18T09:00:01.792Z DEBUG nRFConnect 3.3.0 is supported by the app (^3.2.0)
2020-03-18T09:00:01.792Z DEBUG nRFConnect path: C:\Users\zdiva\AppData\Local\Programs\nrfconnect\resources\app.asar
2020-03-18T09:00:01.792Z DEBUG HomeDir: C:\Users\zdiva
2020-03-18T09:00:01.792Z DEBUG TmpDir: C:\Users\zdiva\AppData\Local\Temp
2020-03-18T09:00:08.442Z INFO Modem port is opened
2020-03-18T09:00:08.448Z DEBUG modem >> AT+CFUN?\x0D\x0A
2020-03-18T09:02:51.075Z DEBUG modem >> AT\x0D\x0A
2020-03-18T09:02:52.076Z ERROR Error: 'AT
' timed out
2020-03-18T09:02:58.827Z DEBUG modem >> AT+CFUN?\x0D\x0A
2020-03-18T09:02:59.828Z ERROR Error: 'AT+CFUN?
' timed out
2020-03-18T09:03:00.489Z DEBUG modem >> AT+CFUN=1\x0D\x0A
2020-03-18T09:03:01.490Z ERROR Error: 'AT+CFUN=1
' timed out

And this is how the LTE Link Monitor looks like:

I am trying to send any command. I am using the same HEX image that worked once yesterday (thingy91_at_client_dfu_2019-11-29_d3130d77.hex). Yesterday I was able to send a few AT commands, the most important for me is the AT+CESQ, I even could receive RSRP notifications!!.

[Heidi]

What version of the Thingy:91 do you have?

When you got it to work, did you see this log at startup?

I know people have had trouble with the serial connection in the past but I believe the issue has been fixed.

Are you running the newest modem firmware version 1.1.1?

2020-03-18T09:11:00.311Z DEBUG modem << 00 NRF_P0               Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.311Z DEBUG modem << 01 NRF_CLOCK            Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.312Z DEBUG modem << 02 NRF_RTC1             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.312Z DEBUG modem << 03 NRF_NVMC             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.314Z DEBUG modem << 04 NRF_UARTE1           Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.315Z DEBUG modem << 05 NRF_UARTE2           Secure\x09\x09SKIP\x0D\x0A
2020-03-18T09:11:00.316Z DEBUG modem << 06 NRF_TWIM2            Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.316Z DEBUG modem << 07 NRF_SPIM3            Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.317Z DEBUG modem << 08 NRF_TIMER0           Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.318Z DEBUG modem << 09 NRF_TIMER1           Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.320Z DEBUG modem << 10 NRF_TIMER2           Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.321Z DEBUG modem << 11 NRF_SAADC            Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.322Z DEBUG modem << 12 NRF_PWM0             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.322Z DEBUG modem << 13 NRF_PWM1             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.323Z DEBUG modem << 14 NRF_PWM2             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.323Z DEBUG modem << 15 NRF_PWM3             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.324Z DEBUG modem << 16 NRF_WDT              Secure\x09\x09SKIP\x0D\x0A
2020-03-18T09:11:00.325Z DEBUG modem << 17 NRF_IPC              Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.327Z DEBUG modem << 18 NRF_VMC              Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.328Z DEBUG modem << 19 NRF_FPU              Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.329Z DEBUG modem << 20 NRF_EGU1             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.330Z DEBUG modem << 21 NRF_EGU2             Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.330Z DEBUG modem << 22 NRF_DPPIC            Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.330Z DEBUG modem << 23 NRF_GPIOTE1          Non-Secure\x09OK\x0D\x0A
2020-03-18T09:11:00.331Z DEBUG modem << 24 NRF_REGULATORS       Secure\x09\x09SKIP\x0D\x0A\x0D\x0A
2020-03-18T09:11:00.331Z DEBUG modem << SPM: NS image at 0x18200\x0D\x0A
2020-03-18T09:11:00.332Z DEBUG modem << SPM: NS MSP at 0x20027fa0\x0D\x0A
2020-03-18T09:11:00.333Z DEBUG modem << SPM: NS reset vector at 0x1a07d\x0D\x0A
2020-03-18T09:11:00.334Z DEBUG modem << SPM: prepare to jump to Non-Secure image.\x0D\x0A
2020-03-18T09:11:00.335Z DEBUG modem << ***** Booting Zephyr OS build v2.0.99-ncs1 *****\x0D\x0A
2020-03-18T09:11:00.335Z DEBUG modem << The AT host sample started\x0D\x0A

[David Zapata]

Well, I think my modem firmware is not the most recent. My version is mfw_nrf9160_1.0.0-24.rc.

I did not save the log file for my only successful connection to LTE Link Monitor. 

Right now, I do not have access to a DK board. As far as I know, the only way to update the modem firmware is by using the DK board. So, I guess my older modem firmware has issues with reliable serial connection to LTE Link Monitor.

Thanks for the help, Heidi :)

[Heidi]

David Zapata said:

As far as I know, the only way to update the modem firmware is by using the DK board.

Yes, unfortunately, as of now, this is the only way. MFW update via MCUboot is coming, though I can't give you a date for that right now. 

[David Zapata]

Just a message for people who have the same issue I had: the ASSET_TRACKER application can be used to connect to the LTE LINK MONITOR. It allows sending AT commands and reading the device response. the AT_CLIENT application is bugged in my opinion.

[Heidi]

Hi,

The new version of nRF Connect for Desktop Programmer now supports modem FW updates via MCUBoot. So you can update to the newest MFW version and see if that solves your problem. 

Best regards,

Heidi