Is FlexIO a bus?

[MarkoIt]

Hi all! :smile:

I'm a new user and i have a doubt.
Is FlexIO a bus?
This doubt born from this:

http://www.realworldtech.com/includes/templates/articles.cfm?ArticleID=RWT021005084318&mode=print

At ISSCC 2005, Rambus presented a paper on the FlexIO interface used on the CELL processor. However, the presentation was limited to describing the physical layer interconnect. Specifically, the difficulties of implementing the Redwood Rambus ASIC Cell on IBM’s 90nm SOI process were examined in some detail. While circuit level issues regarding the challenges of designing high speed I/O interfaces on an SOI based process are in their own right extremely intriguing topics, the focus of this article is geared toward the architectural implications of the high bandwidth interface. As a result, the circuit level details will not be covered here. Interested readers are encouraged to seek out details on Rambus’s Redwood technology separately.

What is known about the system interface of the CELL processor is that the FlexIO consists of 12 byte lanes. Each byte lane is a set of 8 bit wide, source synchronous, unidirectional, point-to-point interconnects.

This:
http://en.wikipedia.org/wiki/Computer_bus

In computer architecture, a bus is a subsystem that transfers data or power between computer components inside a computer or between computers and typically is controlled by device driver software. Unlike a point-to-point connection, a bus can logically connect several peripherals over the same set of wires. Each bus defines its set of connectors to physically plug devices, cards or cables together.

And this:
http://www.webopedia.com/TERM/B/bus.html

All buses consist of two parts -- an address bus and a data bus. The data bus transfers actual data whereas the address bus transfers information about where the data should go.

I think that FlexIO hasn't address bus.
So, Isn't FlexIO or any point-to-point connection a bus?

Thanks, and sorry for my english. I'm italian.

 

[Kryton]

Hi all! :smile:

I'm a new user and i have a doubt.
Is FlexIO a bus?
This doubt born from this:

http://www.realworldtech.com/includes/templates/articles.cfm?ArticleID=RWT021005084318&mode=print



This:
http://en.wikipedia.org/wiki/Computer_bus


And this:
http://www.webopedia.com/TERM/B/bus.html

I think that FlexIO hasn't address bus.
So, Isn't FlexIO or any point-to-point connection a bus?

Thanks, and sorry for my english. I'm italian.

If you can do in-channel signalling, you don't need a seperate address/data bus; it's just part of the Von Neumann standard model (seperate address, control and data wires). HyperTransport is pretty much the same thing, a packet driven bus where data is sent as packets allowing some nifty things (bus splits etc.).

 

[_xxx_]

That separate addres and data thing is ancient, FlexIO is a bus.