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https://opencores.org/ocsvn/funbase_ip_library/funbase_ip_library/trunk
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lanttu |
Simple controller for SMSC LAN91C111 Ethernet PHY
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(http://www.smsc.com/index.php?pid=44&tid=145). It is used e.g. in
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Altera Stratix II FGPA board.
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This controller uses the same interface as DM9000A controller (used in
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DE2 board) and can be connected to the UDP/IP controller exactly in
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the same way.
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LAN91C111 was much more complex to configure and use than DM9000A,
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thus the area usage may be somewhat larger. I tried to compensate for
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extra complexity by simplifying some of the structures.
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You can disable either rx or tx if you don't need them. This is recommended
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to avoid unneeded interrupts and to reduce area usage in case they are not
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needed.
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This has been tested for both send and receive operations with
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different packet sizes, but simultaneous tx and rx operations may
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hang the chip! This is a problem within the chip.
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Also, the chip cannot correctly transmit packets smaller than 66 bytes.
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The workaround is to pad them but this should be done on MAC level (i.e.,
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by the chip) which cannot be done correctly because we cannot override
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the packet size field generated by the chip.
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Due to the numerous problems and instability, I strongly recommend not
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using LAN91C111 if not absolutely necessary.
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Antti Alhonen, February 2012
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