ESP32 Forum

Hello,

I'm using an ESP32-WROOM-32E with 16MB of Flash.

I'd like to understand how ESP32 effectively uses the pins from GPIO 6 to GPIO 11.

I know they are used for the flash memory chip inside, as said here viewtopic.php?t=1250.

I'm using a particular hardware, so not the ESP32-DevKit, where some hardware is connected to GPIO 7 and GPIO 8. It is working well and there aren't problems.
I flash the chip using the DIO mode.

My question is: why is it working? In my opinion it should give errors on the flash!

Well, first of all GPIO7 and 8 are not available on the castellated pads of that module; if you connect stuff to the pads where older modules had GPIO7/8, it won't affect the module. I'd still expect your program to crash when you run e.g. gpio_reset() on GPIO7/8 though.

ESP_Sprite wrote: ↑

Thu Mar 09, 2023 12:42 am

Well, first of all GPIO7 and 8 are not available on the castellated pads of that module; if you connect stuff to the pads where older modules had GPIO7/8, it won't affect the module. I'd still expect your program to crash when you run e.g. gpio_reset() on GPIO7/8 though.

I was looking at the ESP32-WROOM-32 Datasheet v3.1, where from chapter 2 "Pin Definitions" I read that:

Pins SCK/CLK, SDO/SD0, SDI/SD1, SHD/SD2, SWP/SD3 and SCS/CMD, namely, GPIO6 to GPIO11 are connected to the integrated SPI flash integrated on the module and are not recommended for other uses.

However if I look at the new products e.g. ESP32-WROOM-32E Datasheet v1.6, I see that these pins aren't connected anymore (as you said)!

Thank you for this clarification!!