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Using Altera libraries for Nios Dev Board

Hi,

I'm currently working on a project at my university for testing and developing rate based protocols and I've been having some problems with my dev board. I've been using the Altera Nios proffesional dev board (with stratix FPGA). So far I've ran tests with UDP (over 2 dev boards) to test the utilization of my network, which is 100 Mbps and I keep getting numbers just under 10 Mbps. I've done tests on the lines over PC's and they achieve over 40 so I know the line is not the problem. The only thing I can see is that maybe the Ethernet/PHY chip they use defaults to 10 Mbps, even though it says it auto detects to

100 or 10.

I was wondering if anyone has experience with the low level libraries, like lan91c111.c, and could point me in the right direction. I would be satisfied to just get a printout of the register status to see if it is acutally setting itself to 10 Mbps. I've tried to use nr_lan91c111_dump_registers() but it won't give me a printout of the register banks. The lack of documentation also doesn't really help. Any help would be great.

Thanks, Justin.

Reply to
Justin
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Plug both lines into a switch/hub and look at the lights to find out what speed the link is running at.

Put a scope on the wire... (or one of the wires going to the PHY chip)

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Reply to
Hal Murray

Hi Justin,

In addition to what Hal posted about just checking the link speed (and yes, all the C code that handles how the MAC/PHY are reset is in the

91c111 driver), I am curious what your software looks like that is sending Ethernet data? The reason is that the 91c111 *should* boot up and auto-negotiate to the highest speed available. On the other hand, the typical bottleneck when doing embedded etherent communications is with the CPU & protocol stack assembling packets to send.

Example: If you're running Nios at typical clock speeds and are sending UDP data via the plugs stack, it would not surprise me at all if the throughput was around 10Mbit. This can be accelerated quite nicely through some simple HW acceleration (checksum & DMA use up most of the CPU time). So, if the link speed is not the cause of your problems, feel free to send me an email and I can send back an article on this subject and some examples.

Jesse Kempa Altera Corp. jkempa at altera dot com

Reply to
Jesse Kempa

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