Although one would logically expect that to be the case, in my experience
it isn't always true. I suspect it has to do with the high volume in
which PCI Ethernet MAC/PHY chips are used in PCs.
For instance, at one time a Realtek 10/100 MAC/PHY was quoted at a lower
price than the Realtek 10/100 standalone PHY, in the same quantity. I don't
know if that's still the case.
Reply by colin●October 19, 20072007-10-19
On 18 Oct, 15:50, Bryan <bryan.fletc...@avnet.com> wrote:
> Colin,
>
> A MAC+PHY costs more then a PHY, but you save the MAC IP cost and
> gates in the FPGA. It is a good alternative to consider.
>
> Xilinx has a MicroBlaze interface to this type of device, called the
> EPC. They also have an application note that describes how to use it:
> http://www.xilinx.com/bvdocs/appnotes/xapp924.pdf
>
> The app note uses a piece of hardware that is no longer available
> (Avnet P160 Comm 3 module), but you can look at the Spartan-3 Mini-
> Module which also has the 91C111 MAC+PHY.
>
> Bryan
>
>
>
> colin wrote:
> > Hi
>
> > Does anyone have any experiences with connecting a MAC rather than a
> > PHY to a spartan(3e).
>
> > I don't know yet whether to use a microblaze or my own state machine
> > to connect to the ethernet. For microblaze, xilinx cores seem to want
> > just an external PHY but surely a MAC would offload more stuff from
> > the FPGA.
>
> > Any thoughts appreciated.
>
> > Regards
>
> > Colin- Hide quoted text -
>
> - Show quoted text -
Bryan
Thanks for your reply, as a result I've made a much better job of
searching the xilinx website.
Colin
Reply by Bryan●October 18, 20072007-10-18
Colin,
A MAC+PHY costs more then a PHY, but you save the MAC IP cost and
gates in the FPGA. It is a good alternative to consider.
Xilinx has a MicroBlaze interface to this type of device, called the
EPC. They also have an application note that describes how to use it:
http://www.xilinx.com/bvdocs/appnotes/xapp924.pdf
The app note uses a piece of hardware that is no longer available
(Avnet P160 Comm 3 module), but you can look at the Spartan-3 Mini-
Module which also has the 91C111 MAC+PHY.
Bryan
colin wrote:
> Hi
>
> Does anyone have any experiences with connecting a MAC rather than a
> PHY to a spartan(3e).
>
> I don't know yet whether to use a microblaze or my own state machine
> to connect to the ethernet. For microblaze, xilinx cores seem to want
> just an external PHY but surely a MAC would offload more stuff from
> the FPGA.
>
> Any thoughts appreciated.
>
> Regards
>
> Colin
Reply by Mike Treseler●October 16, 20072007-10-16
colin wrote:
> Does anyone have any experiences with connecting a MAC rather than a
> PHY to a spartan(3e).
You probably need both.
The PHY is the magic interface to the wire.
The MAC is a digital interface that makes
it all look like registers to some cpu.
It might be on the PHY chip or it might
be a fpga module.
-- Mike Treseler
Reply by colin●October 16, 20072007-10-16
Hi
Does anyone have any experiences with connecting a MAC rather than a
PHY to a spartan(3e).
I don't know yet whether to use a microblaze or my own state machine
to connect to the ethernet. For microblaze, xilinx cores seem to want
just an external PHY but surely a MAC would offload more stuff from
the FPGA.
Any thoughts appreciated.
Regards
Colin