ESP8266 Community Forum

- Thu Feb 19, 2015 3:39 am #10140 I've experienced the same problem, already with earlier versions of the AT-FW. With the help of Wireshark, I believe I've been able to identify the problem:

Apparently, the ARP process within the ESP8266 somehow "dies" after a while. With the new AT+PING one can at first see the PING-request frame to the target-IP, then the target issues an ARP broadcast to find out the MAC address of the ESP-station, but that ARP request never gets answered by the ESP. Thus no PING-reply…. Same is basically true for all other IP communication.

As a workaround, I then made a permanent entry to the target PC’s ARP table (on Windows use “arp -?” in a command window, you need to be in admin mode to make a static table entry), so there is no need for an ARP address resolution. From then on, the communication did not fail again, regardless if it was from AT+PING or to the device’s TCP-server (AT+CIPSERVER). (My ESP is at 0.9.5 and is run in station mode)

As suggested, I’ve also tried the 0.9.6 b1 beta, but this versions seems to have still the same issues. Besides, it crashes from time to time. So I went back to 0.9.5 which turned out to be rather stable – as far as I can tell by now…

JoeK

- Fri Feb 20, 2015 2:44 pm #10262 Great find, using the arp solution means you can only access the ESP from one machine?
Does anyone know what the purpose is of the function wifi.sleeptype()? I can't find any info on this and it takes parameters like wifi.NONE_SLEEP, wifi.LIGHT_SLEEP, wifi.MODEM_SLEEP?

- Sat Feb 21, 2015 8:13 am #10327 Actually, I wouldn't call it a solution, it's just an interim workaround. It allows you to continue development and test of your own project without constantly wondering if that work has screwed up the ESP or what the heck is going on again…
I’ve seen Athena (from espressif?) is also reading this thread and hopefully will forward this to the developers.
And yes, I'm afraid it works only with the very system with a static entry.

JoeK

- Sat Feb 21, 2015 3:56 pm #10362 I have the same problem. I found out that it only appears in STATION mode. If I use the module in STATION mode I get about 10 to 15 pings working and then it get stuck. If I use the module in SOFTAP mode I can ping for hours without any issue. Sometime it works better in STATION mode if a tcp-server is active and in use. In both cases I ping from a Mac Book Air. In STATION mode the access-point is an Apple Airport Express. In SOFTAP mode the Mac Book is directly connected to the ESP8266. I tried the the ai-thinker firmware 0.9.5, the latest nodemcu firmware binary and self-compiled. Unfortunately I couldn't get the espressif firmware to work, neither 0.9.5 nor 0.9.6. I was able to flash the images, the module starts up an shows ready but it does not accept any AT-command. I was not able to figure out the problem by now.