ESP32 Forum

Hi all, just start using the ESP-WROOM-32 (DevKitC and in a near to come custom board if some prerequisites are met). Want to know if there is a particular reason to tie pin 32 (IO20) to pin 37 (IO23) as seen in DevKitC/J schematics.

According to the ESP-WROOM-32 schematics in data-sheet 10-29-2016 pin 32 should be NC (not connected) and also ESP32 pinout in data-sheet 29-10-2016 doesn't report any GPIO20.

I have forwarded your question to our board design team and will get back to you as soon as they reply.

This has to do with maintaining compatibility with ESP-WROOM module based on pre-production ESP31B chip. If you are designing a board around ESP32, this connection is not needed.

Thanks for the quick answer

That does not make sense. Is io20 connected to io23?

Did you mean to say the connection "is not used" rather than "is not needed".

I think that on the esp32 chip there is no io20 for it is marked NC. On the esp32 chip carrier the esp32 chip has io20 marked NC. The wroom board may or maybe does not connect that NC to its IO23. It appears that no other signal uses the wroom boad pin io23; the reason for all this effort.

I am describing three places the (surface mount) esp32 chip, its (castellated) carrier and the (through-hole) wroom board.