ESP8266 Community Forum

Hi folks,

I've got 3 pieces esp-01 modules. One of them is dead, another is dying in the same way as first have died. What does it mean?
First symptom is that module sometimes sends garbage on its serial port, but after a sw reset it is ok. Appearing garbage gets more often as module is used. At one point module sends only garbage and it cannot be healed further. The complete process takes 1-2 days with continous usage.
One may think this is because I'm using it at 5V. But not, I power the module from 3.3V definitely and I use a voltage divider for ESP's RX pin (it is connected to an 5V arduino). I've double-treble checked it.
Do you have any idea what can be wrong?

Thanks,
D

Hi, posting your code & the garbage (as it often isn’t & is sometimes the only clue as to the problem) may help to sort the problem. These units are very versatile but as we are pushing them far beyond the manufacturers’ original purpose sometimes they need a little more love and attention to perform as expected. This is not a problem that I've seen commonly reported and first impressions suggest an issue linked with time, so running out of memory (but that normally results in a crash / reset) or something getting out of sync, both of which could be cured by changes to the code or periodic resets. That said, there have been a few post recently that have pointed to slowly failing usb to uart devices that where initially reported as serial garbage issues. That can be easily checked by disconnecting the ESP and setting up a loop back without powering off the device. As a side thought what value resistors are you using for the voltage divider?
On seeing your code I’m sure that some of the very informed members will be able to assist.

This is an extremely wild thought ... but in your app, are you continually writing to flash memory? Somewhere in the back of my mind I seem to remember that flash memory writes are only good for a finite number of re-writes before failure. I don't know if it is 1000, 10000 or 1000000 but I might suspect that if you have an app that does nothing but erase and re-write sectors ... you might get a failure that is time related.

kolban wrote:I seem to remember that flash memory writes are only good for a finite number of re-writes before failure.

The Winbond 25Qxx series of Flash chips has an erase/write endurance of 100,000 cycles. That is what they guarantee - the actual number of cycles until failure on a specific chip is probably significantly higher.