How Do SPI, I2C, RS232, and RS485 Interfaces Categorize?

[-EquinoX-]

Homework Statement

1. SPI
2. i2c
3. RS232
4. RS485

Match The following interfaces to their category
a. Asynchronous Serial, point-to-point
b. Synchronous Serial with CS line
c. Asynchronous data bus
d. synchronous with address on the same line as data

Homework Equations

The Attempt at a Solution

My guess so far would be 2-b, 1-c , 4-d, and 3- a... is this true?

 

[MATLABdude]

These are incorrect. Review the definitions of synchronous and asynchronous data transfer, http://en.wikipedia.org/wiki/Comparison_of_synchronous_and_asynchronous_signalling, and then look up the protocols and try to match the protocol with the characteristics.

http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus"
http://en.wikipedia.org/wiki/I2c"
http://en.wikipedia.org/wiki/EIA-485"
http://en.wikipedia.org/wiki/RS-232"

HINT: See which signals are used for communications! Is there a clock line, of some sort? For RS-232, consider whether or not you can daisy chain several serial devices.