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By gutbag
#30430 I'm trying connect an ESP-01 to an AP and I'm finding that as soon as I initiate the connection, the ESP gets into a continuous reset loop, and I can only recover by re-flashing it.

I have the ESP wired with CH_PD, RST, GPIO0 & GPIO2 pulled up to 3.3V, and Tx/Rx connected to an FTDI board. I have 470uF and 100nF capacitors across 0V and 3.3V. I'm using Veroboard so the connections are mostly soldered and solid.

I can connect and use AT commands. I can put the ESP into station mode and it can see several wireless networks, including my own.

So I do:

AT+CWMODE=1 (station)
AT+CWLAP (lists APs)

Then to connect:

AT+CWJAP="my network name","my passphrase"

As soon as I issue this command, the ESP starts resetting every few seconds. If I try to connect to a non-existent network, it fails after a while but doesn't reset. So it's only when it succeeds (I presume) that I get the problem.

I've got some switches to 0V in the GPIO2 and RST lines so I can get back to the bootloader (?) and re-flash the AT firmware version 0.9.2.2.

I see that others have had this problem but I've tried all of their suggestions without success (e.g. decoupling).

I've got ESPs bought months apart and I have the problem with both, so I don't think it's faulty devices, or a batch problem.

Does anyone have any idea what I've missed?

Thanks.
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By Lunix80
#35421 I have the same issue:

I have flashed with this firmware:

AT+GMR

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
OK

When it's not connected to the access point it doesn't reset. After the connection it begin to reset every 3 seconds

It's connected to 3,3v arduino mega pin maybe a lack of current?
User avatar
By stefanfrings
#44098 I encountered the same issue and the same solution.

My environment is:

* ESP-01 module
* with original AT firmware 0902
* 512KB Flash
* Prolific PL2303 USB-UART cable
* Ubuntu Linux 15.10
* esptool.py from https://github.com/themadinventor/esptool

First created a backup:
* sudo ../esptool-master/esptool.py --port /dev/ttyUSB0 read_flash 0 524288 backup.bin

Second, installed the new firmware from SDK 1.5.1 folder bin/at/noboot:
* sudo ~/Downloads/esptool-master/esptool.py --port /dev/ttyUSB0 write_flash 0x00000 eagle.flash.bin
* sudo ~/Downloads/esptool-master/esptool.py --port /dev/ttyUSB0 write_flash 0x40000 eagle.irom0text.bin

Then I connected with a terminal program at 115200 Baud and saw that the module is constantly resetting by the wdt.
So I reinstalled my old backup and that worked.

Then I repeated the same with the files from SDK 1.4.0. This time the modules does not reset anymore. A rough test of functionality looks fine (i removed empty lines):

AT+GMR
AT version:0.50.0.0(Sep 18 2015 20:55:38)
SDK version:1.4.0
compile time:Sep 18 2015 21:32:07
OK
AT+CIFSR
+CIFSR:APIP,"192.168.4.1"
+CIFSR:APMAC,"1a:fe:34:98:d6:e5"
+CIFSR:STAIP,"192.168.2.104"
+CIFSR:STAMAC,"18:fe:34:98:d6:e5"
OK
AT+CIPMUX=1
OK
AT+CIPSERVER=1,23
OK
0,CONNECT
+IPD,0,6:Hallo
0,CLOSED

That looks fine so far. Something must be broken in SDK 1.5.1, am I right?

Anyway I'm happy with that older release, so I don't need any further help at the moment.