Modules not responsive after power disruption

[JBurg (Jan)]

Hello,
I had problems with a cople of RAK3172 in previously running systems which suddenly do not respond anymore to AT commands via UART and do not execute their program. The only way to reactivate them is connecting an ST-LINK/V2 interface using STM32CupeProgrammer and reloading the firmware. Even this is only successful when I perform a full chip erase before.
I suppose this has something to do with the boot mode which might be accidently enabled after a bouncing power source is connected or something like that. I use 10µ and 100n decoupling capacitors and 10k/100n at the RST pin as suggested.
What am I supposed to do with the BOOT pin? I left it floating. Is this correct?
Do you have any other hints how to avoid the problem?

Regards
Jan

[beegee (Bernd Giesecke)]

What firmware version do you have on the RAK3172?

AT+VER=?

[whydont (son lora bükücü)]

Are you sure about using latest firmware for RAK3172? You can go and download latest firmware RAK Download Center and flash it. And try again.

[JBurg (Jan)]

Thank you for the answers.
I had version RUI_3.4.11_RAK3172-E. This is what the RAK Wireless Store shipped 6 weeks ago.
Can I be sure that the issue will be gone after updating with the latest version?

Regards
Jan

[whydont (son lora bükücü)]

I was having same issues like you. Surely, i can’t remember what was the solution for me. Can you try this? https://file.io/jULRB6UMlTeB

[beegee (Bernd Giesecke)]

I was asking for the version because in the older versions was a feature to enter bootloader mode on a double reset signal. This was working well when used as a WisBlock Core module (Reset connected with R/C combination to a button), but caused problems with bouncing reset signals on custom boards.
It is removed since V3.5.x, which I don’t recommend to try, all the V3.5.x are beta and have problems.

V4.0.0 fixes a lot of problems and I am using it now on all my RUI3 devices.

For the BOOT pin, we leave it open in our reference design and on the RAK3172 Evaluation Board and it causes no problems.
The RESET pin should be connected to a R/C combination as shown in the reference design ==> RAK3172 Breakout Board

Latest firmware versions and changelog are in our Download Center

[Wisen (Mike M.)]

This could be related to this issue:

RAK3172 gets bricked if restarted while config is changing

Hello Support, I have been exhaustively trying to resolve an issue for which I might just find the reason: a corrupted configuration saved in the RAK3172 Flash. Background I have developed a product based on the RAK3172 and we currently have around 30 units running in a Pilot before can approve mass production. Those units are going through some tests and after some time in the field, a few of them the RAK3172 module stopped working completely. The symptom is that the RAK3172 module simply d…

[tcpipchip (MIGUEL ALEXANDRE WISINTAINER)]

I had the same problem…ah 100k on reset help me too much