Pullup resistor for EN and BOOT Button

kian79
Posts: 13
Joined: Thu Jun 13, 2019 3:27 am

Pullup resistor for EN and BOOT Button

Postby kian79 » Thu Jun 13, 2019 10:41 am

Hi all,

I am looking at all the different reference designs out there for the ESP32. And I noticed that in some of these designs, the EN and BOOT button has a pull-up resistor to VCC connected. Is this necessary?

Also, in some designs, there is a current limiting resistor between the EN pin and the push button. There is also a current limiting resistor between the IO0 and the BOOT button. Are these necessary too?

I also see capacitors connected across the push button. Some use 0.1uF and some use 1nF. So which one shold I follow?

Thanks!


kian79
Posts: 13
Joined: Thu Jun 13, 2019 3:27 am

Re: Pullup resistor for EN and BOOT Button

Postby kian79 » Fri Jun 14, 2019 12:46 am

Hi chegewara,

Thanks for sharing the link. In the PDF, I saw this line:
The EN pin is used for enabling the chip. Set the EN pin high for normal working mode. There is no RC
delay circuit on the module. It is recommended that users add an external RC delay circuit to the module.

WiFive
Posts: 2549
Joined: Tue Dec 01, 2015 7:35 am

Re: Pullup resistor for EN and BOOT Button

Postby WiFive » Fri Jun 14, 2019 2:17 am

It is sort of dumb that the hardware design guidelines send you to the wroom32 datasheet, but it shows 10k pullup, 0.1uF cap on EN pin.

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