Strange behaviour with all AT firmwares

[cguest]

Hi,

I'm having trouble getting the ESP8266 EX to work as expected. At the moment all I am trying to do is Turn on > scan for networks > Turn off.

I have got this to work but only just, and in a very weird way. In order to get a list of visible APs, I need to:

- Apply power to the CHIP_EN pin -> turn the module on
- Reset using AT+RST, wait for "ready" (tried with an without this, makes not difference)
- wait 1 second
- Put device in softAp + station mode (CWMODE = 3. CWMODE = 1 DOES NOT WORK - more details below)
- Wait 10 seconds
- Send AT+CWLAP every 10 seconds for X number of times. Sometimes this returns nothing until the 3rd time (so after 30 seconds).
- Turn off (disconnect CHIP_EN)
- Repeat.

The module is running off 2.8V, connected to a microcontroller on the same power supply. The SPI flash is a 4Mbit winbond chip with DIO. Here is the circuit


I have tried firmware versions 0.20, 0.25, 0.50, 0.51 (noboot versions). Setting CWMODE=3 makes it work but only with the 0.51 firmware. The other firmwares seemed to return nothing, no matter what I try.

1- Am I missing something?
2- Is there a problem with the circuit?
3- It seems strange to me that I can't just do: AT+CWMODE=1 followed by AT+CWLAP. Why do I need to wait so long before a scan returns something?
4- Why does dual softAP / station mode need to be on?

The antenna is not very good, I know this (-3dB gain) , but it clearly can work when I set it to softAp + Station mode, so I don't know what is wrong.

One last thing
If I create a softAP on my PC, using windows netsh wlan start hostednetwork, the ESP8266 returns this network immediately, it even works in station mode! (AT+CWMODE=1). Is there a problem with non softAps??

[ESP_Faye]

Hi,

AT firmware is too large to fit in 4Mbit flash, could you try it with another module whose flash is larger ?

Sorry for the inconvenience.

[cguest]

Thanks for the reply, but that doesn't seem to be the problem. We have another ESP8266 on an arduino shield (sparkfun) board that also has 4mbit flash, and this works fine

I'm why you say that though, the datasheets have a section for flashing to 4mbit flash - I thought it would work, but that I could not use the bootloader.

Is there something I need to do for it to work on 4mbit ? I did try flashing the sparkfun firmware image to this device and that didn't work either

[Espressif_Kelly]

Dear Cguest,

1.What is the model of this module? or is this module designed by yourselves?

2.From the schematic that attached, the flash part is missing and there are no capacitors besides the crystal.
Please be noted that large frequency error will cause the softAP of your module hard to connect and few APs can be scanned.
Always keep ESP_WAKE high until you need to reset the chip.

3.What is maximum output current of yout cpu that can be provided to wifi?

4.AT firmware needs flash size to be 1024KB and above since SDK_V1.0.1. So please test with AT firmware that based on SDK_V1.0.0.
http://bbs.espressif.com/viewtopic.php?f=46&t=286

5. Please also send your test log to us for debugging.

Thanks.

[cguest]

1. We took the ESP8266EX chip and created our own circuit with crystal, flash etc. Not sure what you're asking but I think the answer is - we designed it ourselves

2. Flash part is there, I just didn't include it in the schematic picture for brievety. It's there and it works though (or we wouldnt be getting anywhere..).
The crystal is pretuned, but point taken - we will include caps in the next design. Would this cause the issue I have described? (no networks found unless in softAP + station mode = 3). It seems unlikely to me - surely it should just never work?

3. The regulator can supply 250mA. We also tried connecting a power supply (limit 2A), this did not help.

4. Ok. As mentioned though - I tested it with rev0.20. I will try again with 0.22

5. The test log is as simple as this:

Code: Select all

AT+CWMODE=1

OK

AT+CWLAP

OK

Do you want the boot up strings and checksums?

Thanks

[cguest]

Just a quick follow up - loaded 0.22 (sdk 1.0.0) with boot 1.3

Code: Select all

AT+RESTORE

OK

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

wdt reset
load 0x40100000, len 1320, room 16
tail 8
chksum 0xb8
load 0x3ffe8000, len 776, room 0
tail 8
chksum 0xd9
load 0x3ffe8308, len 412, room 0
tail 12
chksum 0xb9
csum 0xb9

2nd boot version : 1.3(b3)
  SPI Speed      : 40MHz
  SPI Mode       : DIO
  SPI Flash Size : 4Mbit
jump to run user1

ready


ATE0

OK

AT+CWMODE=1

OK

AT+CWLAP

OK

AT+CWLAP

OK

AT+CWLAP

OK



Tried with CWMODE = 1 and = 3. No luck

[cguest]

Follow up: Changing the baudrate away from 115200 also seems to be intermittent. Using the undocumented IPR=38400 seems to work (sometimes) but:

>AT+UART=38400,8,1,0,3

OK

-- change baud of port --

>ATE0

*

-> Just getting star (or garbled characters in the response)

Sometime sending RST fixes it, but most of the time the unit goes into a weird mode where neither 38400 or 115200 baud rates work - the unit has to be reflashed before it starts working again (basically needs to reset flash settings..)

Don't know if this helps? Maybe it confirms what you were saying about the crystal needing caps?