How does SPI work with ESP32?

UKHeliBob:
When I tried a Google search for ESP32 SPI I got 170,000 hits

I imagine that some of them will have examples

So did I but I could find the details I needed. Instead I tried looking at an example sketch using MCP3008 and SPI on an Uno. Then had a bit of an educated guess that it might work the same on ESP32.

MISO, MOSI, SCK and SS have the correct values for my type of ESP32 corresponding to to SPI3, so apparently that is the default SPI.

The Adafruit_MCP3008 library has either hardware SPI if use begin() with no parameters or software SPI if you specify pin numbers or MOSI etc.

Except that the values it then reads from the ADC channels is different to that read through hardware SPI, with 3.3V on the channel.

Don't really understand what that is about.

Some specific ESP32 SPI example sketches would be nice.