ESP32 Forum

Posted: **Sun Mar 12, 2017 11:44 pm**

The following table is included in Figure 2 in the ESP32 datasheet:

: Screen Shot 2017-03-12 at 5.36.52 PM.png (35.47 KiB) Viewed 5944 times

I am not sure how to interpret this type of truth table. It it saying that both GPIO0 and GPIO2 have to be low to download the boot image? What happens when GPIO0 is low but GPIO2 is high?

I have always seen tables written like this:

: Screen Shot 2017-03-12 at 7.38.11 PM.png (18.05 KiB) Viewed 5944 times

Maybe someone could fill this table in and that would clarify it. Thank you for your help.

Zane Kaminski

Posted: **Mon Mar 13, 2017 6:58 am**

If GPIO0 is 1 then the value of GPIO2 can be 0 or 1 without changing the boot mode (hence the "don't care".)

If GPIO0 is 0 and GPIO2 is 1 (the combination not described in the datasheet truth table) then the ESP32 goes into an undocumented internal test mode.

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