Thanks for the input. Not sure that would apply to full duplex and 100 BT.
Looking at it further I think I've misread the wiki article - I think what
they are referring to is a inline repeater used to double the segment length
of a connection:
PC ---------------------- max length cable -------------------- [MII PHY -
MII PHY] --------------------- max length
cable ----------------------------- PC
This isn't what I need. What I want is my device to provide a repeater port
for a local PC so it doesn't need its own LAN connection:
LAN ------------------------------------ my
device ------------------------------ PC (PC sees the LAN through my device
port)
I think I'll need to goto an Ethernet switch like the Micrel KS8993 unless
someone has another idea how to do it discretely.
--
Allan Williams
"Brendan Gillatt" <brendan@brendanREMOVETHISgillatt.co.uk> wrote in message
news:cslm53l8kca7mcta2fa6scbm2cblp7mql4@4ax.com...
> On Mon, 28 May 2007 21:27:36 GMT, "Al Williams"
> <donotreplydirect@usenewsgroup.com> wrote:
>
>>I read this in Wikipedia near the end of the RMII docs:
>>http://en.wikipedia.org/wiki/RMII
>>
>>"Since the RMII standard neglected to stipulate that TX_EN should only be
>>sampled on alternate clock cycles, it is not symmetric with CRS_DV and two
>>RMII PHY devices cannot be connected back to back to form a repeater; this
>>is possible, however, with the National DP83848 which supplies the decoded
>>RX_DV as a supplemental signal in RMII mode [3]."
>>
>>It seems to imply you can create a simple repeater with two PHY's "back to
>>back" in MII mode. This would be useful for a new device we are working
>>on
>>that needs to daisy chain its Ethernet in and out. I can't find much info
>>on how to do this, anyone done this and if so, how?
>>
>>Thanks.
>
> AFAIK it should be possible - from what I can tell that is what dumb
> ethernet hubs do anyway.
> See http://www.zen22142.zen.co.uk/Circuits/Interface/pethhub.htm for a
> simple 3 port ethernet hub schematic.
> --
> Brendan Gillatt
> www.brendangillatt.co.uk
> GPG: 0x6E265E61
Reply by Brendan Gillatt●May 28, 20072007-05-28
On Mon, 28 May 2007 21:27:36 GMT, "Al Williams"
<donotreplydirect@usenewsgroup.com> wrote:
>I read this in Wikipedia near the end of the RMII docs:
>http://en.wikipedia.org/wiki/RMII
>
>"Since the RMII standard neglected to stipulate that TX_EN should only be
>sampled on alternate clock cycles, it is not symmetric with CRS_DV and two
>RMII PHY devices cannot be connected back to back to form a repeater; this
>is possible, however, with the National DP83848 which supplies the decoded
>RX_DV as a supplemental signal in RMII mode [3]."
>
>It seems to imply you can create a simple repeater with two PHY's "back to
>back" in MII mode. This would be useful for a new device we are working on
>that needs to daisy chain its Ethernet in and out. I can't find much info
>on how to do this, anyone done this and if so, how?
>
>Thanks.
AFAIK it should be possible - from what I can tell that is what dumb
ethernet hubs do anyway.
See http://www.zen22142.zen.co.uk/Circuits/Interface/pethhub.htm for a
simple 3 port ethernet hub schematic.
--
Brendan Gillatt
www.brendangillatt.co.uk
GPG: 0x6E265E61
Reply by Al Williams●May 28, 20072007-05-28
I read this in Wikipedia near the end of the RMII docs:
http://en.wikipedia.org/wiki/RMII
"Since the RMII standard neglected to stipulate that TX_EN should only be
sampled on alternate clock cycles, it is not symmetric with CRS_DV and two
RMII PHY devices cannot be connected back to back to form a repeater; this
is possible, however, with the National DP83848 which supplies the decoded
RX_DV as a supplemental signal in RMII mode [3]."
It seems to imply you can create a simple repeater with two PHY's "back to
back" in MII mode. This would be useful for a new device we are working on
that needs to daisy chain its Ethernet in and out. I can't find much info
on how to do this, anyone done this and if so, how?
Thanks.
--
Allan Williams