ESP8266 Community Forum

- Fri Jun 30, 2017 10:03 pm #67785 I'm working on my first ESP-01 project. When I use AT+CWJAP to connect to my Wifi Router, it connects, gets an IP, hangs for several seconds, and resets. It then loops into connecting and resetting over and over. However, if I connect to my iPhone's Wifi Hotspot, I don't get resets. Anyone know why one AP causes resets and the other doesn't? This seems to be the same problem reported at http://bbs.espressif.com/viewtopic.php?t=1216, but there was no solution posted.

AT+GMR returns:
AT version:0.51.0.0(Nov 27 2015 13:37:21)
SDK version:1.5.0
compile time:Nov 27 2015 13:57:56

Wifi Router: Hitron CODA-4582

iPhone: 5s

I am connected to the ESP using a serial connection (FTDI USB-to-Serial), and sending AT commands to connect to Wifi.

Connecting to my phone, I get:
AT+CWJAP="iPhoneHotspot","MyPassword"

WIFI CONNECTED
WIFI GOT IP

OK
AT+CIFSR

+CIFSR:STAIP,"172.16.1.1"
+CIFSR:STAMAC,"18:fe:34:9a:00:00"

Connecting to my Wifi router, I get:
OK
AT+CWJAP="MyWifiRouter","MyPassword"

WIFI CONNECTED
WIFI GOT IP

<a few seconds pause here>

ets Jan 8 2013,rst cause:4, boot mode:(3,7)

wdt reset
load 0x40100000, len 23620, room 16
tail 4
chksum 0x00
load 0x3ffe8000, len 948, room 4
tail 0
chksum 0x1c
load 0x3ffe83b8, len 3912, room 8
tail 0
chksum 0x51
csum 0x51
r⸮ùl⸮Ğb⸮:
ready
WIFI CONNECTED
WIFI GOT IP

<a few seconds pause, then it resets again in a loop>

- Sat Jul 01, 2017 9:31 am #67795 Some additional info:
I've tried two different ESP-01 modules, they both behave the same, although I get different rst causes - I've seen 1, 2, and 4 with this.

Also brought up a Linksys E3200 AP, and the ESP can connect to that fine. Seems to only be the Hitron CODA 4582 router/modem/AP that it doesn't like. Unfortunately, that's the AP I need to connect to.

- Sat Jul 01, 2017 3:17 pm #67804 Unexplained resets generally caused by inadequate 3.3V

- Sat Jul 01, 2017 8:47 pm #67813 What atexit8 says: the ESP is very picky about power.

Make sure it's a stable 3.3V and can provide enough current (>500mA, but preferably 1A to be on the safe side).
Do not trust your USB -> RS232 TTL board is adequate, since it most of the time isn't.

Also: some bugs are resolved since version 1.5, you might want to try the latest firmware version (v.2.1.0 at the moment).

Assumption is the mother of all f*ckups. At least: that's what I'm assuming.