Question about the Def'n of registers and buffers

[CityK]

I came across this Corsair page wherein the following is written:

Why are they called Registers and not Buffers?

In the language of system designers, buffers are known as "asynchronous". Whatever signals are on the input pins appear directly on the output pins (after a few nanoseconds). Correspondingly, registers are known as "synchronous" components. When new signal values appear on the input pins, they don't show up on the output pins until (a few nanoseconds after) the next tick of the system clock.

Now is there something wrong here or is am I missing something. ie. the use of synchronous and asynchronous seems to be reversed. Can someone explain. (P.S. I am aware of how registered RAM works, so no explaination is needed there....I am just very unclear on this "language of system designers").

Cheers, CK

 

[P5-133XL]

Asyncronous - Not sync'ed to the clock (Shows up immediately without waiting for the clock)
Syncronous - Sync'ed to clock (Shows up with the clock pulse)

 

[CityK]

Ahh, got it. Thanks for the clarification Mark.

Rather poorly written by Corsair, if you ask me.

CK

 

[blakerwry]

I believe i am correct in saying the following:


registers are meant to hold the value of something until they either lose power or are filled with something else(your RAM is made up of registers).. You can send or recieve information the the rise/fall of a clock cylce


buffers on the other hand are temp storage places where data comes in from one source and is destined for another, usually these 2 sources run at slightly or even wildly different clock speeds and/or protocols and thus the buffer is needed to momentarily hold information while it goes between sources.

 

[cas]

When working with computer systems, we tend to think of a buffer as a temporary storage space (eg print buffer). Applying this thinking to circuit design can be misleading.

A buffer is strictly electrical, and is typically used to increase the drive strength of a signal, while a register actually contains flip flops to store information. The output of a buffer always follows its input by a small number of nanoseconds, while a register always outputs the contents of its flip flops (although it may flow through).

There is nothing inherently synchronous or asynchronous about a register. New data may be latched at any time. By feeding the latch input with a clock signal however, one can build a synchronous system.

 

[cas]

There is nothing inherently synchronous or asynchronous about a register.

Actually, this should read “There is nothing about a register that inherently limits it to synchronous or asynchronous designs.” At a certain level, all common logic is inherently asynchronous.

 

[CityK]

Ahh, interesting. Thanks Cas.