Consolidated Interface
for Fiber or Copper PHY
-----------------------
Robert Grow
XLNT Designs, Inc.
15050 Avenue of Science
San Diego, CA  92128
619-487-9320
bob@xlnt.com



Objectives
----------
o  Accommodate Different Physical Coding Sublayers
o  Create Logical Interface Similar to Media Independent
   Interface
o  Speed Independent (100/1000)
o  Support Mapping to PLS Primitives



Frame Mapping
-------------
            __________________________
            |        |   |  |     |   |
            |PREAMBLE|SFD|DA| ... |FCS|
            |________|___|__|_____|___|
                      MAC FRAME
__________________________________________
|           |        |   |  |     |   |   |
|INTER-FRAME|PREAMBLE|SFD|DA| ... |FCS|EFD|
|___________|________|___|__|_____|___|___|
                      MII FRAME



PHY Characteristics
-------------------
o  Requirements and Assumptions
   - Independent of PCS
   - Byte Oriented (1/8 of Bit Rate)
   - Allow Multibyte Delimiters
   - Support Carrier Extension
o  Possible Additional Requirements
   - Multiple Frames per Access
   - Defer Signalling
   - Definition of an MII



OUTPUT & INPUT _UNITs
---------------------
o  I - Idle link
o  SSD - Establishes byte alignment, may be multibyte sequence
o  D <7:0> - 256 data values
   - SFD is D relative to SSD
o  EFD - May be multibyte, terminates frame
o  H - Indicates transmitter error or invalid receive code
o  CE - Carrier extension



MII Like Encoding
-----------------
  Signal    Transmit    Receive
  Clock     TX_CLK      RX_CLK
  x_UNIT        TX_C        RX_C
            TX_D[7:0]   RX_D[7:0]
o  Minimize number of signals
o  Backward compatible to MII



Control Code Encoding
---------------------
  TX_C    TX_D[7:0]    Meaning
  RX_C    RX_D[7:0]
   0      DDDDDDDD     Data
   1      XXXXXX00     Idle
   1      XXXXXX10     Idle_Defer
   1      0XXXX101     Start Stream Sequence
   1      0XXXX001     End Frame Delimiter
   1      0XXXX111     Carrier Extension
   1      1XXXXXXX     H - Error



Example PCS Mappings
--------------------
o  Preamble
   |SSD| D | D | D | D | D | D |SFD| D |

   | K | D | D | D | D | D | D |SFD| D |

   | S1| S2| S3| D | D | D | D |SFD| D |

o  End Frame
   | D |EFD| I | I | I | I | I | I |

   | D | T | R | I | I | I | I | I |

   | D | T | R | R | I | I | I | I |



Conclusion
----------
o  Simple MAC-PHY interface
o  Extensible for Proposed Enhancements
o  Adaptation of MII
o  Simple mapping to PLS primitives
o  Support Electrical Interface