Choosing Bi-port Ethernet Chip

I've searched the web and I've only found two chips that can interface
with 2 ethernet ports. They are:

    AX88742
    AX88783

On the manufacturer's website, they describe the 42 variant as:

    32-bit PCI 2-Port 10/100M Fast Ethernet Controller

And the 83 variant as:

    Non-PCI 8/16/32-bit 2-Port 10/100M Fast Ethernet Controller

Could someone please explain to me what this means?

Also, and this probably sounds like a clueless question, but I don't
know if either chip is a fully-fledged microcontroller, or whether
they're an ethernet controller on its own that needs to be hooked up
to a microcontroller? Anyone know?

On May 6, 4:17 pm, Tom=E1s =D3 h=C9ilidhe <t...@lavabit.com> wrote:
> I've searched the web and I've only found two chips that can interface
> with 2 ethernet ports. They are:
>
>     AX88742
>     AX88783
>
> On the manufacturer's website, they describe the 42 variant as:
>
>     32-bit PCI 2-Port 10/100M Fast Ethernet Controller
>
> And the 83 variant as:
>
>     Non-PCI 8/16/32-bit 2-Port 10/100M Fast Ethernet Controller
>
> Could someone please explain to me what this means?
>
> Also, and this probably sounds like a clueless question, but I don't
> know if either chip is a fully-fledged microcontroller,

No

> or whether they're an ethernet controller on its own that needs to be hook=
ed up
> to a microcontroller?

Maybe

> Anyone know?

Yes

On May 6, 6:17=A0pm, Tom=E1s =D3 h=C9ilidhe <t...@lavabit.com> wrote:
> I've searched the web and I've only found two chips that can interface
> with 2 ethernet ports. They are:
>
> =A0 =A0 AX88742
> =A0 =A0 AX88783
>
> On the manufacturer's website, they describe the 42 variant as:
>
> =A0 =A0 32-bit PCI 2-Port 10/100M Fast Ethernet Controller
>
> And the 83 variant as:
>
> =A0 =A0 Non-PCI 8/16/32-bit 2-Port 10/100M Fast Ethernet Controller
>
> Could someone please explain to me what this means?
>
> Also, and this probably sounds like a clueless question, but I don't
> know if either chip is a fully-fledged microcontroller, or whether
> they're an ethernet controller on its own that needs to be hooked up
> to a microcontroller? Anyone know?


These both appear to be combined dual Ethernet switch ports and a
(single) Ethernet controller (more or less), with no real
intelligence, except for some IP offload processing (and whatever they
needed internally for the bridging function).

The PCI chip has the electronics to attach to a PCI bus, while the non-
PCI one has a more traditional "block of RAM" like interface.  If you
have a PCI bus on your system, go with the former, if you don't
(rather more likely with a microcontroller), go with the latter.  The
non-PCI version appears to support different sizes of data bus, making
it easy to attach to various width microcontrollers.

Both of these appear to support some bridging functions internally
(hence the word "switch" in the description).  In short, it ends up
looking like a three port Ethernet switch, with your microcontroller
attached to one of the ports.  These are not dual port Ethernet
controllers in the sense that they connect to different networks.
IOW, I don't think you could build a two port router with one of these
devices, unless there is a different mode of operation than the one
being touted.

But there's no particular reason to use a dual port chip, unless one
of them happens to fit your needs particularly well.  Two single port
chips are the more common solution.  Or like I mentioned earlier, one
internal Ethernet port on your microcontroller plus an external
single.

If you=92re looking for a single chip microcontroller with multiple
Ethernet ports, look at some of Freescale=92s stuff.  For example, the
MPC852T has a fast Ethernet port plus two serial controllers that can
run a 10Mb Ethernet port each (for a total of three Ethernet ports).