Hello, What is maximum communication speed over ethernet on ENC28, pls.
A G120 SOM can send about 450 kByte/sec via UDP (hope I have it correct in mind, but > 300 KByte/sec. for sure).
Please be aware that this depends on packge size and SPI clock frequency.
The default frequency is set to 8000 kHz. The maximum of ENC28 is 20000kHz which works fine for me.
I measured it with 1400 Bytes/package using UDP and 20000 kHz. In a loop which does nothing else than sending the same byte array over and over (minimum overhad).
Also code that runs in parallel (other threads) will reduce this.
I want use G120 for HTTP server. So can I count with 300KB/s?
Your best bet is to set up a test and try it yourself. I would plan conservatively, however. Especially if you’re doing any server-side processing, it will not be a speed demon.
I can’t try it. I haven’t got G120 and Ethernet module. I want to make master board for home automatization (G120). And I want HTTP API for control system from PC and phone.
Now is my server Panda II with ethernet shield, but Panda has got small memory. I tried HTTP server on Panda, but it was very slow. So I want make HTTP API (JSON,…) only, no full web server with pages.
Speed will not be a concern. You could do that kind of work at 1kb/sec or even less.
Yep, a simple Home Automation server doing JSON type requests surely will not have massive speed requirements, and certainly shouldn’t be handling hundreds of requests/second. Can’t really see why you think Panda is not performing either - are you really trying to do just REST/JSON type actions on your Panda?
@ Brett - No. I tried only full web server with pages on SD card. But panda has got small memory, so I have to buy new board (G120). Now it’s impossible put my program on panda.
I was worried about the SPI speed. But if you say it will be good, so I’ll believe you. 
I think what we’re all saying is that SPI speed isn’t the limiting factor, it’ll still be other things you need to do, but removing html overhead from your web services means you should be less impacted by those, but throughput on the network layer won’t be a real bottleneck (and Panda can have heaps of memory if you’re careful and think small I don’t mind if you use that as a reason to get CFO approval for an upgrade though :) )
I don’t know why is my program so big. Maybe if I delete HTTP server class (http://www.tinyclr.com/codeshare/entry/363) and use some simple HTTP class I will get enough space for my program.
Ok. Thanks for replies. Now which reply mark as answer.