ESP32-EVB_Rev_D Reset Circuit

[dlt99]

I have just been looking at ESP32-EVB_Rev_D schematic. The reset button grounds the ESP_EN line, which seems ok when you look at the ESP device, EN pin 3; however, the schematic shows that ESP_EN is also connected to the PWR_FLAG (see U8, pin 2. bottom left hand corner of schematic). PWR_FLAG is actually the 3V3 line (see U2, voltage regulator output top left of schematic).

This means that the reset button seems to ground the +3V3 line to perform a reset!

Is this true, or is the schematic in error?

(If it is true, a better solution might be to supply the regulator chip EN pin through a resistor and ground that instead.. remove the connection to the ESP, as it will reset when the power is interrupted...)

[LubOlimex]

> PWR_FLAG is actually the 3V3 line (see U2, voltage regulator output top left of schematic).

No. Search for the following string "PWR_FLAG KiCAD" to find more information about PWR_FLAG.

[dlt99]

Oh, I see. The PWR_FLAG is not a net label but a net <attribute>, declaring the net as a "supplier of power". PWR_FLAG attributes are not necessarily "joined together" - eg, could be one on +5V and one on +3V3. (Hope that little summary is of use to others...)

Thanks LubOlimex!

[LubOlimex]

I thank you for raising this matter. Also I couldn't have summarized the "PWR_FLAG" attribute better than you.