Does anybody know where I can find atmel's USI as SPI driver?
The data sheet tells you pretty much how. See also AVR319 on the Atmel web site (and maybe AVRFreaks).
Until Black Lives Matter, we do not have "All Lives Matter"!
Maybe start with Atmel's application note AVR319: Using the USI module for SPI comunication.
You can put lipstick on a pig, but it is still a pig.
I've never met a pig I didn't like, as long as you have some salt and pepper.
© 2021 Microchip Technology Inc.