I am wondering if it is possible to use the 16k of available memory in the wiznet ethernet module for storing html data to be sent later?
I know the wiznet will use the standard arduino ethernet library and you can easily create web server and client with that, but I am hoping to get some extra storage, for example, if I were able to put my static html in to the wiznet with a sketch, then have a different sketch that simply tells the wiznet to output the data in it's memory adding in the dynamic data (variables) at the same time.
AFAICT and as I recall it, the memory used is SRAM and the content seems to be preserved between power cycles. This is probably not guaranteed to be the case--it is not EEPROM.
The chip can handle up to 4 hardware sockets and there is a low-level method for allocating the RAM to be used as Rx/Tx buffers for each socket. There are also a low level methods for reading/writing bytes of the buffers.
In theory it should be possible to allocate memory to a socket but not use that socket. I don't know if that is guaranteed to be preserved however. You might be able to configure a Tx buffer at least to not be overwritten one would think.
I think you would need to experiment to find out for sure--and it might be implementation specific. You would also need to work at a lower level than the Ethernet library--but if you restrict the socket numbers you use one should be able to coexist with the other, I think.
I have thought about doing this (as you might have guessed ) but I haven't actually tried it out.
--Phil.
P.S. I might have forgotten something else I have written here so it might be worth reading it yourself.
