A few good SPI-related documentation

1, Http://www.gammon.com.au/spi

This article explains in great detail the SPI communication of Arduino.

2,http://www.brianhensley.net/2012/07/getting-spi-working-on-raspberry-pi.html

This is the SPI communication that speaks Raspberry Pi.

3,http://mitchtech.net/raspberry-pi-arduino-spi/

This article describes the communication between PI and Arduino via SPI, but it is possible to damage the PI because there is no level shift between the two.

4,http://www.lijingquan.net/raspberry-pi-arduino-spi.html

This is the Chinese version of the previous article.

5,http://arduino.cc/en/reference/spi

This is the part of the Arduino documentation that describes the SPI.

A few good SPI-related documentation