MAC vs MAC+PHY

What's the difference?
-- 
Randy Yates
Digital Signal Labs
http://www.digitalsignallabs.com

On Sun, 18 May 2014 19:44:19 -0400, Randy Yates
<yates@digitalsignallabs.com> wrote:

>What's the difference?


One is just a MAC, and needs a separate PHY, the other does both?

Think of the MAC has a higher level, dealing with frames, and the PHY
as dealing with the , *ahem*, physical layer - encoding, signaling,
etc.  In a 10mb Ethernet implementation you might use the same MAC for
10base-5, 10base-2, 10base-T or 10base-F, but (obviously) would need a
different physical layer (PHY) for each version.  The interface
between the MAC and PHY is not standardized, but there are some
de-facto/common interfaces.

These days many devices support only a single type of connection, and
there's little or no advantage to a separate PHY, and the integrated
device makes your parts count go down.

Randy Yates wrote:
> What's the difference?
>

One is Layer 1, the other is Layer 2.

Having to do integration of a MAC and separate PHY has advantages
but you have to then understand the MMI. Hopefully,
that's already in the BSP that comes with your eval board
and is the same unless your board went off the reservation, in
which case...

Given the choice, all other things being equal, an integrated
MAC+PHY is the lazy man's way.

-- 
Les Cargill