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Registered: ‎10-09-2007

LocalLink TEMAC vs Ethernet MAC Lite



Could someone please give me some idea or point me in the direction of something that will give me some idea of the differences between the LL-Temac and the Ethernet MAC Lite in ISE 11.3?  The most obvious difference is the lack of 1000Mb operation which isn't an issue to me, but apart from that are there any other issues with the Lite version that might make it less than optimal to use with the xilinx git-supplies Linux kernel?


We're not doing anything spectactuar with the enthernet interface - it's used at 100Mb (and sometimes 10Mb) with a fixed IP address (ie no DHCP or anything "exotic") for the local program to communicate over a couple of TCP and UDP sockets with a remote host.  Are there any advantages to the LL_Temac?  Actual data throughput is probably not an issue, we need a few hundred Kb.


I'm having trouble with resources in the design - as soon as I add a timer (XPS Timer/Counter) I run out of FFs, and I'm hoping that I can use the Lite, which presumably uses less resources than the Tri-Mode one, but I want to be sure it'll work "as expected" with Linux and our application. 


An earlier version of the hardware (on ISE9.1) used a Temac that wasn't a LL_Temac which seemed to leave plenty of resources.  Apart from that, and the usual version upgrades in the opther IP cores in the design, there is no difference between this hardware and the older stuff, so I'm suspecting the LL_Temac of using a lot more resource than the old Temac, and hoping the Lite will resolve that.


I can't seem to find anything that compares them directly, though.




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Registered: ‎05-27-2009

The LLTemac is a subset of LocalLink interfaces that support high speed data transport. In this case the Temac or Tri mode Ethernet Media Access Controller is an ethernet engine that connects to the system memory via the Local Link. While some may disagree, many view the Local Link interface as THE fundamental Xilinx paradigm for the design of high speed data systems. Of course high performance also entails higher complexity. With this in mind, an Etherent MAC Lite should be viewed as a simpler to understand, and lower perfomance mechanism for moving data. A designer can do himself no greater service than to thorougly master the Local Link, as an understanding of this interface allows one to design systems capable of processing data at GBaud rates.
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