5208, Data Cache, Ethernet buffers

Discussion created by JENS PECHMANN on Sep 11, 2006
Latest reply on Sep 13, 2006 by Melissa A Hunter

I'm working on an ethernet application with the 5208. I store the buffer descriptors for the FEC in the internal SRAM but the ethernet buffers itself in the SDRAM. Everything works well with the data cache turned off. But i would like to use the data cache in my application.
Right now i'm working with the M5208EVB. I want to use 1 MB for buffers (not cached). How can i set this up? Is it possible to use the data cache and the fec with the ethernet buffers residing is SDRAM at the same time?

I already tried the following:
I double the size of the SDRAM (SDCS0[CSSZ] = 64 MByte instead of 32 MByte). This gives me the same memory twice. Now i set up the cache to cache only the first 32 MByte. I use the linker to take care that the buffers are accessed at an uncached address. It seems to work fine. The question here: Is it ok to do it like this? What happens with the SDRAM refesh? Is the SDRAM refreshed twice? Is there a better way to do it?