STM32WL and LoRaWAN Endnode example - resets occuring

MDaub.1 · ‎2025-11-10

I am new to the NUCLEO WL55JC1 and wanted to experiment with LoRaWAN.

I've followed the YT series on the topic, especially the 3rd part (https://www.youtube.com/watch?v=8KNfrWoa1fw&t=26s). My End node is properly joined and connected to the things network. I am using the 868 MHz band in EU.

However after several successful transmits that I can observe on the UART, the device seems to reset after a timeout. What could be the reason?

...
###### ========== MCPS-Confirm =============
420s356:VDDA: 254
420s356:temp: 21
420s360:TX on freq 868500000 Hz at DR 0
420s363:SEND REQUEST
422s009:MAC txDone
427s041:RX_1 on freq 868500000 Hz at DR 0
427s239:IRQ_RX_TX_TIMEOUT
427s239:MAC rxTimeOut
427s996:RX_2 on freq 869525000 Hz at DR 3
428s055:IRQ_RX_TX_TIMEOUT
428s055:MAC rxTimeOut

###### ========== MCPS-Confirm =============
430s364:VDDA: 254
430s364:temp: 21
430s364:Next Tx in  : ~3169 second(s)

FATAL: read zero bytes from port
term_exitfunc: reset failed for dev UNKNOWN: Input/output error
daubsi@t14:~$ picocom -b 115200 /dev/ttyACM0
picocom v3.1

port is        : /dev/ttyACM0
flowcontrol    : none
baudrate is    : 115200
parity is      : none
databits are   : 8
stopbits are   : 1
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
hangup is      : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv -E
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,
logfile is     : none
initstring     : none
exit_after is  : not set
exit is        : no

Type [C-a] [C-h] to see available commands
Terminal ready
10s042:TX on freq 868100000 Hz at DR 0
11s527:MAC txDone
16s558:RX_1 on freq 868100000 Hz at DR 0
16s756:IRQ_RX_TX_TIMEOUT
16s756:MAC rxTimeOut
17s558:RX_2 on freq 869525000 Hz at DR 0
17s756:IRQ_RX_TX_TIMEOUT
17s756:MAC rxTimeOut

###### = JOIN FAILED
20s048:TX on freq 868100000 Hz at DR 0
21s533:MAC txDone
26s564:RX_1 on freq 868100000 Hz at DR 0
26s762:IRQ_RX_TX_TIMEOUT
26s762:MAC rxTimeOut
27s564:RX_2 on freq 869525000 Hz at DR 0
27s762:IRQ_RX_TX_TIMEOUT
27s762:MAC rxTimeOut

###### = JOIN FAILED
30s054:TX on freq 868300000 Hz at DR 0
31s539:MAC txDone
36s570:RX_1 on freq 868300000 Hz at DR 0
36s768:IRQ_RX_TX_TIMEOUT
36s768:MAC rxTimeOut
37s570:RX_2 on freq 869525000 Hz at DR 0
37s768:IRQ_RX_TX_TIMEOUT
37s768:MAC rxTimeOut

###### = JOIN FAILED
40s060:TX on freq 868500000 Hz at DR 0
41s544:MAC txDone
46s576:RX_1 on freq 868500000 Hz at DR 0
48s385:MAC rxDone

###### = JOINED = OTAA =====================
###### MCRootKey:   7D:F7:6B:0C:1A:B8:99:B3:3E:42:F0:47:B9:1B:54:6F
###### MCKEKey:     8C:B8:66:5E:0C:0E:0B:64:5B:2E:D9:E4:8A:19:27:7C
###### AppSKey:     01:64:04:D4:7C:87:EA:5D:64:05:54:CE:D0:23:B3:C3
###### NwkSKey:     B1:CB:70:8B:57:55:08:E3:77:0F:41:C1:3E:4A:C4:E8
###### DBIntKey:    7A:C4:7C:65:FE:25:9B:B6:54:BD:26:35:19:F8:9C:8E
###### DevEUI:      00:80:E1:15:xx:xx:xx:xx
###### AppEUI:      01:01:01:01:01:01:01:01
###### DevAddr:     26:0B:2E:16
50s063:VDDA: 254
50s063:temp: 22
50s067:TX on freq 868100000 Hz at DR 0
50s070:SEND REQUEST
51s716:MAC txDone
56s748:RX_1 on freq 868100000 Hz at DR 0
56s946:IRQ_RX_TX_TIMEOUT
56s946:MAC rxTimeOut
57s703:RX_2 on freq 869525000 Hz at DR 3
57s762:IRQ_RX_TX_TIMEOUT
57s762:MAC rxTimeOut

###### ========== MCPS-Confirm =============
60s071:VDDA: 254
60s071:temp: 21
60s075:TX on freq 867300000 Hz at DR 0
60s078:SEND REQUEST
61s724:MAC txDone
66s755:RX_1 on freq 867300000 Hz at DR 0
66s954:IRQ_RX_TX_TIMEOUT
66s954:MAC rxTimeOut
67s710:RX_2 on freq 869525000 Hz at DR 3
67s770:IRQ_RX_TX_TIMEOUT
67s770:MAC rxTimeOut

###### ========== MCPS-Confirm =============
70s079:VDDA: 254
70s079:temp: 22
70s083:TX on freq 867500000 Hz at DR 0
70s085:SEND REQUEST
71s732:MAC txDone
76s763:RX_1 on freq 867500000 Hz at DR 0
76s961:IRQ_RX_TX_TIMEOUT
76s961:MAC rxTimeOut
...

300s258:VDDA: 254
300s258:temp: 21
300s262:TX on freq 867500000 Hz at DR 0
300s265:SEND REQUEST
301s912:MAC txDone
306s943:RX_1 on freq 867500000 Hz at DR 0
307s141:IRQ_RX_TX_TIMEOUT
307s141:MAC rxTimeOut
307s898:RX_2 on freq 869525000 Hz at DR 3
307s958:IRQ_RX_TX_TIMEOUT
307s958:MAC rxTimeOut

###### ========== MCPS-Confirm =============
310s266:VDDA: 254
310s266:temp: 22
310s270:TX on freq 867500000 Hz at DR 0
310s273:SEND REQUEST
311s919:MAC txDone
316s951:RX_1 on freq 867500000 Hz at DR 0
317s149:IRQ_RX_TX_TIMEOUT
317s149:MAC rxTimeOut
317s906:RX_2 on freq 869525000 Hz at DR 3
317s965:IRQ_RX_TX_TIMEOUT
317s965:MAC rxTimeOut

###### ========== MCPS-Confirm =============
320s274:VDDA: 254
320s274:temp: 22
320s278:TX on freq 868500000 Hz at DR 0
320s281:SEND REQUEST
321s927:MAC txDone

FATAL: read zero bytes from port
term_exitfunc: reset failed for dev UNKNOWN: Input/output error
daubsi@t14:~$ picocom -b 115200 /dev/ttyACM0
picocom v3.1

port is        : /dev/ttyACM0
flowcontrol    : none
baudrate is    : 115200
parity is      : none
databits are   : 8
stopbits are   : 1
escape is      : C-a
local echo is  : no
noinit is      : no
noreset is     : no
hangup is      : no
nolock is      : no
send_cmd is    : sz -vv
receive_cmd is : rz -vv -E
imap is        : 
omap is        : 
emap is        : crcrlf,delbs,
logfile is     : none
initstring     : none
exit_after is  : not set
exit is        : no

Type [C-a] [C-h] to see available commands
Terminal ready
10s042:TX on freq 868100000 Hz at DR 0
11s527:MAC txDone
16s558:RX_1 on freq 868100000 Hz at DR 0
16s756:IRQ_RX_TX_TIMEOUT
16s756:MAC rxTimeOut
17s558:RX_2 on freq 869525000 Hz at DR 0
17s756:IRQ_RX_TX_TIMEOUT
17s756:MAC rxTimeOut

###### = JOIN FAILED
20s048:TX on freq 868500000 Hz at DR 0
21s533:MAC txDone
26s564:RX_1 on freq 868500000 Hz at DR 0
26s762:IRQ_RX_TX_TIMEOUT
26s762:MAC rxTimeOut
27s564:RX_2 on freq 869525000 Hz at DR 0
27s762:IRQ_RX_TX_TIMEOUT
27s762:MAC rxTimeOut

###### = JOIN FAILED
30s054:TX on freq 868100000 Hz at DR 0
31s539:MAC txDone
36s570:RX_1 on freq 868100000 Hz at DR 0
36s768:IRQ_RX_TX_TIMEOUT
36s768:MAC rxTimeOut
37s570:RX_2 on freq 869525000 Hz at DR 0
37s768:IRQ_RX_TX_TIMEOUT
37s768:MAC rxTimeOut

###### = JOIN FAILED
40s060:TX on freq 868500000 Hz at DR 0
41s544:MAC txDone
46s576:RX_1 on freq 868500000 Hz at DR 0
46s774:IRQ_RX_TX_TIMEOUT
46s774:MAC rxTimeOut
47s576:RX_2 on freq 869525000 Hz at DR 0
47s774:IRQ_RX_TX_TIMEOUT
47s774:MAC rxTimeOut

###### = JOIN FAILED
50s066:TX on freq 868300000 Hz at DR 0
51s550:MAC txDone
56s582:RX_1 on freq 868300000 Hz at DR 0
58s391:MAC rxDone

###### = JOIN FAILED
60s072:TX on freq 868100000 Hz at DR 0
61s556:MAC txDone
66s587:RX_1 on freq 868100000 Hz at DR 0
66s786:IRQ_RX_TX_TIMEOUT
66s786:MAC rxTimeOut
67s587:RX_2 on freq 869525000 Hz at DR 0
69s397:MAC rxDone

###### = JOINED = OTAA =====================
###### MCRootKey:   7D:F7:6B:0C:1A:B8:99:B3:3E:42:F0:47:B9:1B:54:6F
###### MCKEKey:     8C:B8:66:5E:0C:0E:0B:64:5B:2E:D9:E4:8A:19:27:7C
###### AppSKey:     51:F3:83:D5:12:6F:89:77:53:CA:E5:97:C4:85:44:05
###### NwkSKey:     EE:F4:5F:B1:25:40:1E:C1:0C:A9:35:F8:8C:92:59:64
###### DBIntKey:    7A:C4:7C:65:FE:25:9B:B6:54:BD:26:35:19:F8:9C:8E
###### DevEUI:      00:80:E1:15:xx:xx:xx:xx
###### AppEUI:      01:01:01:01:01:01:01:01
###### DevAddr:     26:0B:B7:81
70s075:VDDA: 254
70s075:temp: 22
70s079:TX on freq 868100000 Hz at DR 0
70s082:SEND REQUEST
71s728:MAC txDone
76s759:RX_1 on freq 868100000 Hz at DR 0
76s958:IRQ_RX_TX_TIMEOUT
76s958:MAC rxTimeOut
77s714:RX_2 on freq 869525000 Hz at DR 3
77s774:IRQ_RX_TX_TIMEOUT
77s774:MAC rxTimeOut

###### ========== MCPS-Confirm =============
80s083:VDDA: 254
80s083:temp: 22
80s086:TX on freq 868500000 Hz at DR 0
80s089:SEND REQUEST
...

The proplem occurs after various times, sometimes 400 seconds, sometimes 300 and without any apparent reason. The device is currently connected to a notebook via USB, so has a stable power supply.

Only 2 green LEDs are constantly lit, no red LED is lit.

In general the whole setup seems to be somewhat unstable. During the day I had the device powered by a USB powerbank and while it eventually joined the network I had all kinds of interruptions and timeout errors that could be seen on The Things network console WebUI. Sometimes everything worked for 30min and then it stopped completely and I didn´t receive any new messages until I powercycled the board. During all the time the red LED was flashing every couple of seconds.

Later on I went for a walk outdoors and carried the board with me. I checked that the next gateway node is about 500m away from my position but the whole time I was outside not a single message was transmitted to TTN and the board did not even join the network apparently (Red LED was again flashing).

What could be the reason?