I want to design a software driver to interface the AT91RM9200 EMAC with a tcp-ip stack. As neither the datasheet nor their support makes this clear I presume:
I have to use the ARM9 MMU to set up a memory region in external RAM (SDRAM), which is neither cachable nor writebuffered.
Only this way the software can communicate safely with the EMAC especially the "receiver buffer pointers".
Is this the way it is supposed to be handled ?
I presume the ARM9 core will not "snoop" with it's cache any DMA activities inside the AT91RM9200.
Raymund Hofmann