What PINs are defined for SPI?
thanks help
The default pins for hardware SPIs are not available - one of them is used for the Ethernet, the other is used for the SD card (and GPIO12 is used for Ethernet power enable-disable).
However, you can use any free GPIO for SPI as long as you re-define the hardware SPI, albeit this limits their clock to 40Mhz (down from 80Mhz). This reduction in speed is because everything goes through an extra GPIO layer.
You should read more about hardware SPI at the ESP32 wiki here:
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/spi_master.html