RAK3172 Randomly Loosing config when power is cut/re-supplied

LPWAN Modules / EVBs RAK3172
1

The RAK3172 I am using seems to be loosing the:

  1. DevEUI
  2. AppEUI
  3. AppKEY
  4. Work Mode
  5. Region

Randomly when I remove and then re-apply power.
I am using it as a Modem, (I did not re-program the RAK3172)
I have only used 4 AT commands:

AT+APPEUI=XXX...
AT+APPKEY=XXX...
AT+JOIN...
AT+SEND...

I wanted the chip to keep its default DevEUI (like on the sticker)

I have not reset the chip using the reset command, and I did not update the FW.

AFTER seeing this issue, I did update the firmware to the latest version (released on the 25th)
I then set all of the config settings. AppEUI, DevEUI, AppKEY, Work Mode, Region.
The problem still randomly reoccures.

Any idea what may be going on?
Might it be a power issue? The power is coming from a 3.6v battery directly (within the upper range that the datasheet shows).

Thank you very much!

2

Hello @Kevin192291

Loosing means

  • reset to factory default
    or
  • set to zeros?
3

It is changing to all Zeros,
Factory defaults would be much better as I would be able to use the defaults on TTN

4

Is this

  • RAK3172 on a custom PCB
  • RAK3272 Breakout Board
  • RAK3271-E Evaluation Board

Normally, if the user settings are erased or damaged, it should start up with the factory defaults, but not with all zeros.

I will send this issue to our R&D team.

5

This is a custom board.
If you need, I can send the schematics.
Is there a way to do it in a more private way though?
Could this be a problem I have caused with a bad connections or something?

I found by re-setting the settings everytime, I am able to work-around the issue.
But this costs time, power. (and possibly write cycles?)

6

And an additional question, if it happens, are they permanent on zeros, or does another reboot solve the problem and the settings are back?

Did you connect the RST pin to anything or is it floating?
Could you try to put a pullup (10k) on the RST pin?

7

Can you send the problem to [email protected]. That is our customer support channel and we can talk more private there.

1 Like
8

Yes, the RST pin is currently Floating. I have made designed like that before using the RAK3172, I was under the impression that there is an internal pullup. is the not correct?

9

There is no pullup inside the RAK3172.
If you take the Breakout Board schematics as reference, there is a 10k/100nF on the RST line.

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10

I have just experienced the same issue as described in this thread.
The software version on the 3172 module is:

AT+VER=RUI_4.0.0_RAK3172-E

I left the module running overnight, re-programmed it this morning and I now see the following after running the AT commands:

AT+DEVEUI=?, AT+APPEUI=? and AT+APPKEY=?

I get the following response:

AT+DEVEUI=0000000000000000 OK
AT+APPEUI=0000000000000000 OK
AT+APPKEY=00000000000000000000000000000000 OK

Fortunately I made a copy of these values so hopefully I can re-load them.
The reset circuitry looks like this:
reset-rak3172
Thanks in advance for any help you can offer.
Update - I have successfully reloaded the IDs/keys and established a network connection with uplink data been received. I am still concerned that this may randomly occur when the board is installed. Is there any information regarding cause and mitigation?

11

Hi Neil,

Can you update to RUI3 V4.0.6, that should solve the problem.

12

Hi Bernd,

Thank you for your prompt reply. I have looked for a pre-built version of v4.0.6 here:
https://github.com/RAKWireless/RAK-STM32-RUI/tree/main

and the last commit was:

https://github.com/RAKWireless/RAK-STM32-RUI/commit/cb8b6bd97b418c77f908e3a987b9f81d7c457733

This is slightly confusing - is that commit for a library for v4.0.2 or was the wrong tag used?
I just want to use the prebuilt v4.0.6 hex file from the repo.
Thanks again.
Neil.

13

Hi Bernd

We are about to ship 150+ of the RAK3172 with v4.0.5

Can you please advise if this error is likely to occur in this version ?

Kind Regards

Paul

14

V4.0.5 is not the latest.
Update in ArduinoIDE to the latest BSP to be safe.

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15

Hi Beegee

Thanks for the reply regarding 4.0.5 and 4.0.6 but

It is a lot of work to unbox 150 x RAK3172sensors , unscrew , reprogram , screw back up , test and rebox

Can RAKwireless be more specific about the bug found and the work around etc so we can understand the risk .

We use Slave Processor with AT Commands (EU868) and the power / battery is removed only 3-5 times in the like of the RAK3172

Thank you for digging deep on this problem

Kind Regards
Paul

16

Hi Beegee

The change note states
RUI-899 - Encryption key of RAK3172 P2P getting erased - Does this bug also apply to OTA mode ?

KR
Paul

17

Hi Paul,

(1) Use Board Manager of Arduino IDE to get latest release. Commits shown in the Github Repos might not be included in the latest official release.

(2) You can find the bug fixes in the Changelog and in the Release Notes.
More details are in RAK3172 does not respond to AT+ commands after 48 days

There were two main issues. First was a timer overflow which caused the modules to hang. Second was an NMI triggered by fluctuating power supply which caused the modules to hang. Both are solved in V4.0.6

(3) LoRaWAN mode does not have this problem. Encryption is handled by the LoRaWAN stack with either the keys received during OTAA join or with the keys set with AT command (or API call) for ABP.