Basic docs on SPI registers? (Arduino Uno)

Projects Networking, Protocols, and Devices
1

I'm reading a program that uses SPI, and it has all these references to things like SPCR, SPE, MSTR, SPR1, and SPR0 which aren't defined anywhere.

Poking around, I was able to glean that SPCR is a register and the others refer to bits in the register, but I can't find any definitive documentation on them. I'm also curious to know how many other magic variables are hiding in the Arduino. Can someone point me in the right direction? (I'm using an Arduino Uno.)

The closest I could come was:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1242101969

Thanks! 8)

2

You need to look at the data sheet for the Atmel ATMega processor.

It explains the systems inside the chip like the SPI interface without mercy.

Also, this guide from another thread is useful.