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RE: [ethmac] fifo reset



27-Feb-02
 
   yxzhou Hi,
 
           Not sure what altera-wizard/xilinx-core-gen provide as I myself only use them for "pure" memorey/pll module but why not build a rewind fifo yourself ?
 
the basic concept is to have two set of couters let say radd (read address) and radd_mark (read address mark)
 
at start both are 0
 
as you read the radd is incremented.
 
at the end of the packet you move the radd_mark to the radd position.
 
so far nothing intresting
 
now let say radd=50 and radd_mark=50 and another packet is trasmited
 
and let say when radd=60 you get a collision
 
all you do is load the radd with the radd_mark and Walla you get a rewind fifo.
 
keep in mind that for full signal (in the write side) you MUST use the radd_mark as otherwise you might over run the data and can't later re-trasmite it.
 
have a nice day
 
   Illan
-----Original Message-----
From: zou.yixin@zte.com.cn [mailto:zou.yixin@zte.com.cn]
Sent: Tuesday, February 26, 2002 10:31 PM
To: ethmac@opencores.org
Subject: [ethmac] fifo reset


Hi,
  In my design ,Fifo is used to store the frame data that is to be transmitted.When col occurs during transfer,
the frame will be re-transmitted.I want to reset the read point(read address) only when col occurs.Then it is not
neccessary to transfer data from memory to fifo.But i can not find any core in xilinx that provides the function to
reset read point.Who can give me a suggestion on how to reset the read point? Or any better methods ?
Thanks.
  yxzhou