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Wifi radio not working

Posted: Wed Feb 18, 2015 6:58 pm
by systemsconnect
Hi,

It seems our divider circuit connected to the ADC of the ESP8266ex has damaged the wifi radio. Our configuration is running at 10 seconds deep sleep interval and after waking up, the voltage of the battery is read from the ADC, wifi connects and sends the data over wifi and sleeps again.

The supply voltage has a maximum of 3.6V. To the ADC a divider circuit brings down the voltage lower than 1V. The divider circuit resistors R1 is 10MOhm a R2 is 2.7MOhm. The divider circuit is directly connected to the battery positive and ground.

Somehow, after running a couple of hours fine, the wifi fails to connect and it will never connect again (even after a power off and on).

I've tested multiple chips and all of them seems to be broken after a while. Everything else still works, so it does wakeup and goes to sleep again but it does not connect to wifi anymore. After flashing the firmware again it still does not connect. If I take an other ESP8266 chip with the same firmware it works.

Has somebody any idea what the problem could be?

Re: ADC damages Wifi radio?

Posted: Wed Feb 18, 2015 8:07 pm
by reaper7
maybe try to set for a tests:

Code: Select all

deep_sleep_set_option(1)

RF_CAL after deep-sleep wake up, there will be large current.

before execute system_deep_sleep

Re: ADC damages Wifi radio?

Posted: Wed Feb 18, 2015 8:49 pm
by systemsconnect
Thanks for your answer, but I'm already calling deep_sleep_set_option(1) before deep sleep. This does not solve the problem.

Re: ADC damages Wifi radio?

Posted: Wed Feb 18, 2015 9:03 pm
by reaper7
what about others options? maybe (0) ?
maybe some bug, and RF is not calibrated ?

Re: ADC damages Wifi radio?

Posted: Wed Feb 18, 2015 11:11 pm
by systemsconnect
OK, I've tried option 0 but still it does not connect. I don't understand why it should working in the first hours and just stops after a while. I've tried multiple ESP chips.
If the ADC is not connected it's perfectly working all the time so the firmware seems OK.

Re: ADC damages Wifi radio?

Posted: Thu Feb 19, 2015 9:30 pm
by systemsconnect
OK, it does seems not related to the ADC. A new test run did face the same problem and does not use the ADC.
I don't know what te problem is.

Re: ADC damages Wifi radio?

Posted: Fri Feb 20, 2015 5:24 pm
by joostn
Perhaps your firmware is somehow corrupting the flash configuration area used by the ESP libs (flash blocks 7C - 7F)?
You might try erasing those blocks and filling with zeros.

Re: ADC damages Wifi radio?

Posted: Fri Feb 20, 2015 11:41 pm
by systemsconnect
OK, that works! Many thanks. It does somehow get corrupted, what's wrong with my firmware?

Please, can you explain why these address get corrupted and why did you think this address causes the problem?

Re: ADC damages Wifi radio?

Posted: Sat Feb 21, 2015 1:51 am
by joostn
Well I guess your firmware is writing to flash? You should make sure it does not touch flash blocks 7c to 7f.

Re: Wifi radio not working

Posted: Tue Feb 24, 2015 5:17 pm
by systemsconnect
Strangely, the firmware is not writing to flash. I don't know why these addresses get corrupted. It's strange why are they affected after running a while and not from the first run? Apparently, somehow the firmware makes something corrupt during runtime.