ESP8266 Community Forum

Hi Neil,

We've had several discussions about pull-ups (and pull-downs).

In my "humble" opinion one should never leave an unused input floating. They do have some built-in pull-ups and pull-downs, but they are very weak (comparable to 50-100 kOhms). They're probably not even resistors but cmos current sources.

Any kind of electric or static noise will make the input go up/down/stray or may even crash the esp.

So really, just add pull up and pull down resistors wherever there is an input floating.

I completely agree with Erik, especially after, for those who remember, "vigourous" discussions I had with "tytower" guy who never admitted that I was right on that subject.

The internal PullUps/PullDowns are really too weak !
Even Espressif has written contradictions about it in their Hardware User Guide on page 14/15, section 2.2.2 :

There is an internal pull-up in the CHIP_EN pin, so no external pull-up is needed.
[...]
There exists internal pull-up resistor in the reset pin, Pin32, which can be left dangled when it is not used.
[...]
Note that this pin cannot be dangled.

Many people mentioned in this forum that simply by touching the floating RES pin will produce a reset.

So, personally, I'm using 10K or 4K7 resistors on all those pins, RES, CH_PD, GPIO15, GPIO2 and GPIO0.

Thanks guys ... attached is the new image that will appear in the November release ...

Good evening Neil,
I just downloaded your book, but did not see at a glance how to fix my problem.

I uploaded a file with an error and the ESP-12e is stuck in a loop that reboots every few seconds. I cannot send any command to it except for the reboot command. I am working with ESPlorer v0.2.0-rc2. Is there a trick to stop it or delete what is in memory?
I flashed the board several times with nodemcu, it does not help.
I successfully uploaded code from the arduino ide and everything works fine there.
When I flash it again with nodemcu, the old code comes back and does not let me do anything before it reboots the esp.

Please let me know what I should do.
Thank you