BOOT as GPIO input

[DJKWAS]

Hi,
I'm trying to design my esp32 based project and I would like use BOOT pin (pull-up during startup) as GPIO configured as output.
It is going to control another cheep e.g. shift register. I'm uploading software via uart with programator like in picture below:
https://dl.espressif.com/dl/schematics/ ... v4-sch.pdf (USB UART + SWITCH part).

I know that during startup there is sensing procedure in esp32, which is pulling up BOOT pin and I have to ensure that design would be safe for sensing procedure and by accidental pushing boot switch when BOOT pin is used as output.

Do you think if I add additional resistor between BOOT connector and IO0 would be enough?

idea.png (23.46 KiB) Viewed 546 times

[ESP_Sprite]

It depends. Easiest way to use a bootstrap pin is to A. use it as an output only only, connected to an input pin on the other chip, and B. to make sure that whatever level the pin has on bootup does not affect the other chip in any way.