Watchdog trigger when starting wlan in WLAN.STA mode

[bartvandeenen]

Hi all

If I run the function below in /flash/main.py it reliably triggers the watchdog, and the same if I call the function after a successful boot.
However, if I execute the lines in this function via the repl one by one, I don't trigger the watchdog. Is this a timing issue ?

def setup_wlan_client():
    wlan=WLAN(mode=WLAN.STA)
    net = [net for net in wlan.scan() if net.ssid == 'bart'][0]
    wlan.connect(net.ssid, auth=(net.sec, '*****'), timeout=5000)
    while not  wlan.isconnected():
        pass
    print(wlan.ifconfig())

Here's my os info:

os.uname()
(sysname='LoPy', nodename='LoPy', release='0.9.3.b2', version='d78a5a3 on 2016-11-05', machine='LoPy with ESP32')

Here's the watchdog log after successful hard reset.

...
mode : softAP(24:0a:c4:00:85:0d)
dhcp server start:(ip: 192.168.4.1, mask: 255.255.255.0, gw: 192.168.4.1)
dhcp server start:(ip: 192.168.4.1, mask: 255.255.255.0, gw: 192.168.4.1)
MicroPython d78a5a3 on 2016-11-05; LoPy with ESP32
Type "help()" for more information.
>>> setup_wlan_client()
mode : sta(24:0a:c4:00:85:0c)
n:4 0, o:6 0, ap:255 255, sta:4 0, prof:6
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0

connected with bart, channel 4
Task watchdog got triggered. The following tasks did not feed the watchdog in time:
Tasks currently running:
CPU 0: MicroPy
Aborting.
Guru Meditation Error: Core   0 panic'ed (Unhandled debug exception)
Register dump:
PC      :  400e6d17  PS      :  00060036  A0      :  800f2088  A1      :  3ffd51f0  
A2      :  0000000a  A3      :  0000000a  A4      :  00000004  A5      :  00000000  
A6      :  00000000  A7      :  fffffff8  A8      :  00000000  A9      :  3ffd5160  
A10     :  00000000  A11     :  3ffdd7b3  A12     :  3ffd512f  A13     :  00000030  
A14     :  00000000  A15     :  00000000  SAR     :  00000011  EXCCAUSE:  00000001  
EXCVADDR:  00000000  LBEG    :  4000c2e0  LEND    :  4000c2f6  LCOUNT  :  ffffffff  
CPU halted.

[bmarkus]

I would replace the pass inside of the while loop with a small delay, like 100ms or so for testing.

[bartvandeenen]

This post is deleted!

[bartvandeenen]

@bmarkus
your suggestion is correct, and resolves the issue!

So the good solution is:

while not wlan.isconnected():
    tim.sleep_ms(50)

But pass or machine.idle() in the while loop trigger watchdog expiry!