I've got WROOM-32 from espressif and are CE/FCC marked already
Rgds,
Frenk

hi,
that is perfect addition to Neil's hint about pin mapping and fits into . Now it is much more clear. Thank you.

Hi,
after checking schematics of WROOM32(ESP32/S seems to be the same), 6 pins SD0 - SD3, CMD and CLK (GPIO8 - GPIO11) are used as datalink between on-board flash and ESP32. They are also exposed as external pins on a board. What is actual purpose of this exposed pins? Is there any option to limit ...

thank you for a very useful hint/link/thinking. Have a lot to study. thanks again:)

hi,
on ESP32 pinout(images from web), it is specified that TXD0=GPIO1, RXD0=GPIO3, RXD1=GPIO9, TXD1=GPIO10. Latter two are also used for SPI access to flash.
in ESP32 doc (esp_wroom_32_datasheet_en.pdf) on page 9, there is specified that UART0/UART1 can use arbitrary GPIO pin. Is this correct?
Rgds ...

Thank you for a nice hint. That is what I was looking for.
Rgds.

Hi,
1.) has ADC any option to "define" external reference?
2.) is there any pin to "access" internal ADC reference ?

is ADC reference voltage available as an output pin on a board? what exactly ADC_H is?

is there any info on ADC I/O support? I mean channels, type of chanel, internal, external reference, speed?