ESP8266 Community Forum

- Wed Oct 24, 2018 2:16 am #78833 I just received a bunch of ESP-01 boards, and have connected one to my computer through an FTDI USB to serial converter. Using a terminal emulation program on my compuer, I'm able to communicate with the ESP-01 up to a point. Typing in the simple "AT" command, the ESP-01 correctly responds with "OK." So then, following the first example in the Expressif "AT Command Examples" documentation, I tried setting up an access point and then connecting to my wireless router:
AT+CWMODE=3
OK
AT+CWJAP="MyNetworkName","MyPassword"

I get an "OK" response after the CWMODE command, but after the CWJAP command there is nothing for a few seconds, and then I get about 20 lines of what appears to be diagnostic data, and finally, the message "WIFI CONNECTED" but no "OK" message. And at this point there is no response to any further commands that I try to type. From this point on, the ESP-01 sends out the same lines of data every 8 seconds:

Code: Select all ets Jan  8 2013,rst cause:4, boot mode:(3,6)

wdt reset
load 0x40100000, len 2408, room 16
tail 8
chksum 0xe5
load 0x3ffe8000, len 776, room 0
tail 8
chksum 0x84
load 0x3ffe8310, len 632, room 0
tail 8
chksum 0xd8
csum 0xd8

2nd boot version : 1.6
  SPI Speed      : 40MHz
  SPI Mode       : QIO
  SPI Flash Size & Map: 8Mbit(512KB+512KB)
jump to run user1 @ 1000

å‚‹.Ï8.Çn¿‰æ.r‹ÿÚn„b..å.é„l`.ƒæ.rí8.«∆l. #..Ä..r..å‚úÁ…8ÇÏ.Ú. 1..Ä..r..å‚‹ÁI8Ç.é˚.0±..Äl.r..r..é.√πl¿ƒû.bfl‰..ååb‡ƒb‡..íl8‡Ïé€å8..b¿‰∏~ín‡.n‹íú..ƒ....€˚yNÄ..‚..å..Çåé.l.íå.Çå.Ïå.ûl`..>`..ƒ‹í‹ƒb..Ç..ílé8..Ä.fl.åû.bfl‰..Ç..|å.r..r..
ready
WIFI CONNECTED

This goes on indefinitely. From the second line that says "wdt reset" it leads me to believe that the processor is running amok in unprogrammed memory, and finally the watchdog timer does a reset. So it looks like the someone must have forgotten a return statement somewhere in the code.

I've discovered that after the above data gets sent to the terminal, there's about a one second window when it will accept an AT command. I was able to enter the address query command AT+CIFSR, and got the correct response showing that it had indeed connected to the router and had been assigned an IP address, but the wdt timeout loop still continued.

Has anyone else encountered this problem?

- Wed Oct 24, 2018 9:02 pm #78853 While I still don't know why it was doing this continuous WDT reset, it does appear that I'm back in business. I'd mixed up station mode and SAP mode. I should have been using Station mode. I was also using deprecated AT commands from obsolete documentation (and there seems to be a tremendous amount of obsolete documentation floating around).

- Thu Oct 25, 2018 3:24 am #78859 What are you powering the ESP-01 with?
Something tells me (though you're not exactly stating) you're trying to power it with the 3.3V output of the FTDI convertor (like all bad examples floating around internet are doing).

Please note that the ESP needs at least 300mA - 500mA to work with: using the radio needs a lot of power and a FTDI convertor isn't capable of delivering this.

The latest AT firmware (dated 24 aug 2018) and accompanying manual (dated 18 oct 2018) can be found on the Espressif website.

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

- Thu Oct 25, 2018 11:43 am #78876 I did check the power requirements before hooking it up and noted that the USB/serial converter could supply only 50mA. So, I am using a separate 3.3V supply.